Cooper v. Xpertes, LLC (Nev. 2026): Undisclosed Impeachment Videos and “Mystique” Prejudice—Abuse of Discretion Without a New Trial Absent Material Prejudice

1. Introduction

In Cooper v. Xpertes, LLC, appellant Dale Cooper sued three entities involved in producing a Las Vegas fashion convention—Xpertes, LLC (general services contractor), Encore Event Technologies, LLC (electrical services), and Urban Exposition, LLC (event host)—after an exhibition booth wall fell on her during teardown. The parties disputed who pulled an electrical cord that allegedly destabilized the wall. Cooper, who did not report injury at the scene, sued sixteen months later claiming a traumatic brain injury and sought $15 million.

After a 28-day jury trial, the jury found none of the defendants negligent. The district court denied Cooper’s NRCP 59 motion for new trial, finding the trial “fundamentally fair.” On appeal, Cooper raised multiple trial-management issues: a Batson challenge, for-cause juror challenges, attorney misconduct, late insurance disclosure, evidentiary rulings (including impeachment by social media videos), and a spoliation adverse-inference instruction.

2. Summary of the Opinion

The Nevada Supreme Court affirmed. It held:

• The district court conducted (and correctly resolved) the full Batson analysis; race-neutral reasons for the strike defeated Cooper’s claim of purposeful discrimination.
• The district court erred in not excusing one juror for cause (Juror #7), but Cooper waived/failed to timely develop the required showing of prejudice; no new trial.
• Defense counsel committed misconduct by alluding to excluded matters and attempting to weaponize excluded/limited video evidence, violating NRPC 3.4(e), but the record supported the district court’s finding of no material prejudice—especially given the trial length and the negligence verdict (making some misconduct damages-focused).
• Xpertes’s late disclosure of an excess policy violated NRCP 16.1 disclosure duties but was harmless because Cooper did not cogently show prejudice.
• The court identified an abuse of discretion in the manner undisclosed social-media videos were used (creating “mystique” when the jury knew damaging evidence existed but could not view it), but deemed the error harmless in the context of the full trial and verdict.
• The district court acted within its broad discretion in declining Cooper’s requested fact-specific spoliation instruction and offering a generic adverse-inference instruction that Cooper ultimately declined.

3. Analysis

A. Precedents Cited (and How They Shaped the Decision)

1) New-trial standards and prejudice

• Cox v. Copperfield, 138 Nev. 235, 239, 507 P.38d 1216, 1222 (2022): supplied the core two-part new-trial requirement—NRCP 59(a)(1) grounds plus prejudice “materially affecting” substantial rights. It also informed harmless-error review and the discussion of impeachment videos and credibility as a “central defensive issue.”
• Nelson v. Heer, 123 Nev. 217, 223, 163 P.8d 420, 424-25 (2007) (quoting Edwards Indus. v. DTE/BTE, Inc., 112 Nev. 1025, 10386, 923 P.2d 569, 576 (1996)): reinforced the abuse-of-discretion standard and reluctance to reverse absent “palpable abuse.”
• Wyeth v. Rowatt, 126 Nev. 446, 465, 244 P.3d 765, 778 (2010): anchored the harmless-error principle in evidentiary contexts (“When an error is harmless, reversal is not warranted.”).
• Carver v. El-Sabawi, 121 Nev. 11, 14-15, 107 P.38d 12838, 1285 (2005), and Cook v. Sunrise Hosp. & Med. Ctr., LLC, 124 Nev. 997, 1007, 194 P.3d 1214, 1220 (2008): supplied the “miscarriage of justice” framing and clarified the need for record-based showing that, but for the error, a different result might have been reached.

2) Batson doctrine and review

• Diomampo v. State, 124 Nev. 414, 422-23, 185 P.3d 1031, 1036-37 (2008) (quoting Walker v. State, 113 Nev. 853, 867-68, 944 P.2d 762, 771-72 (1997)): set clear-error review and “great deference” to Batson factfinding.
• Williams v. State, 134 Nev. 687, 689-90, 429 P.3d 301, 305-06 (2018), and Watson v. State, 130 Nev. 764, 775-76, 335 P.3d 157, 166-67 (2014): provided the three-step framework and explained step-one’s “not onerous” burden while rejecting the idea that striking a single minority juror alone necessarily establishes a prima facie case.
• Ford v. State, 122 Nev. 398, 403-04, 182 P.3d 574, 578 (2006): defined race-neutrality at step two and pretext analysis at step three (“implausible or fantastic” justifications may indicate pretext).
• Kaczmarek v. State, 120 Nev. 314, 332, 91 P.3d 16, 29 (2004), and United States v. Novaton, 271 F.3d 968, 1003 (11th Cir. 2001): supported the court’s treatment of the record—once race-neutral reasons are offered, the analysis effectively proceeds to step three; disputes about step-one become functionally moot.
• Perez v. Talley, No. 79094, 2021 WL 5629280, at *2 (Nev., Nov. 30, 2021) (Order of Affirmance), and Edwards v. Emperor’s Garden Rest., 122 Nev. 317, 330 n.38, 130 P.3d 1280, 1288 n.38 (2006): were used to reject underdeveloped pretext arguments and inadequately briefed points.

3) For-cause juror challenges: bias, rehabilitation, and prejudice

• Boonsong Jitnan v. Oliver, 127 Nev. 424, 431-34, 254 P.3d 623, 628-30 (2011): was pivotal. It supplied (i) the functional test (“prevent or substantially impair” juror duties), (ii) the requirement to examine the “record as a whole,” and (iii) the additional appellate requirement: even if denial of a for-cause challenge was erroneous, the moving party must show prejudice (i.e., an unfair or partial juror actually served).
• Weber v. State, 121 Nev. 554, 581, 119 P.3d 107, 125 (2005): cautioned that “detached language” of fairness is insufficient; courts look beyond formulaic rehabilitation.
• McDonald v. W.-S. Life Ins. Co., 347 F.3d 161, 172 (6th Cir: 2003): was quoted (via Jitnan) to emphasize deference is “not no review.”
• Khoury v. Seastrand, 132 Nev. 520, 530 n.2, 377 P.3d 81, 88 n.2 (2016): supported waiver—arguments raised meaningfully only in a reply brief are deemed waived.

4) Attorney misconduct and remedy calibration

• Lioce v. Cohen, 124 Nev. 1, 17-20, 174 P.3d 970, 980-82 (2008): supplied the governing framework: the significance of objection/admonishment status and the burden to show misconduct so extreme that admonitions could not cure it, as well as standards of review (de novo on whether conduct was misconduct; abuse of discretion on new-trial remedy).
• Gunderson v. D.R. Horton, Inc., 130 Nev. 67, 74-75, 319 P.3d 606, 611 (2014): reinforced that a new trial is generally warranted only where misconduct affects substantial rights (linked to NRCP 59(a)(1)(B)).

5) Evidence admissibility, scope, nondisclosure, and “trial by ambush”

• M.C. Multi-Family Dev., LLC v. Crestdale Assocs., Ltd., 124 Nev. 901, 913, 193 P.3d 536, 544 (2008), and Cox v. Copperfield, 138 Nev. at 239: supported deferential review of evidentiary calls absent “palpable abuse.”
• Johnson v. Egtedar, 112 Nev. 428, 436, 915 P.2d 271, 276 (1996): supported abuse-of-discretion review for scope of testimony.
• Acosta v. State, 141 Nev., Adv. Op. 40, 573 P.3d 1258, 1268-69 (2025), and Turner v. State, 136 Nev. 545, 554-55, 473 P.3d 438, 448 (2020): were used to frame the “trial by ambush” concern and the centrality of bad faith and prejudice to relief when undisclosed evidence appears.
• Allianz Ins. Co. v. Gagnon, 109 Nev. 990, 997, 860 P.2d 720, 725 (1993): supported rejecting arguments lacking record citations.
• Dyrhauge v. Black, No. 85979, 2024 WL 2795693, at *2-3 (Nev., May 30, 2024) (Order of Affirmance): supported that nondisclosure of impeachment evidence does not automatically require a new trial.
• Coe v. Centeno-Alvares, No. 51216, 2009 WL 3189841, at *2 (Nev., Sept. 28, 2009) (Order of Affirmance): was central to the court’s critique of the video-handling procedure because it can create “mystique and curiosity” when jurors know damaging evidence exists but cannot see it.
• Hill v. Parker, Nos. 80451, 81138, 2021 WL 2911508, at *1 (Nev., July 9, 2021) (Order of Affirmance): supported allowing impeachment of an expert using undisclosed public documents relevant to credibility.

6) Spoliation and adverse inference instructions

• Bass-Davis v. Davis, 122 Nev. 442, 447, 134 P.3d 108, 106 (2006): supported “broad discretion” over jury instructions, including adverse inferences.
• Banks ex rel. Banks v. Sunrise Hospital, 120 Nev. 822, 831, 102 P.3d 52, 59 (2004): rejected Cooper’s claim of entitlement to a fact-specific instruction; Banks allowed one in that case but cautioned the holding should be “narrowly construed.”

B. Legal Reasoning

1) Batson: the court treated the record as a full three-step analysis

Cooper argued the district court impermissibly stopped at step one (prima facie inference) when the defense struck the only remaining Black veniremember. The Supreme Court read the record differently: the trial judge ruled after hearing three race-neutral reasons tied to the juror’s “COVID-induced memory loss and brain fog” and how that overlapped with a disputed “brain injury” case and trial-length concerns. That sequence, plus the judge’s later written explanation, supported that the court reached step three.

Critically, the Supreme Court emphasized what was missing on appeal: Cooper did not develop a pretext showing (e.g., disparate treatment of similarly situated non-Black jurors). Without that, the race-neutral reasons stood and the Batson ruling was affirmed under clear-error deference.

2) For-cause challenges: error without reversible prejudice

Applying Boonsong Jitnan v. Oliver, the Supreme Court concluded both Juror #49 (pro-plaintiff bias based on concussion experience) and Juror #7 (skepticism of personal injury claims and view that plaintiff faced a “huge mountain”) showed bias that was not unequivocally set aside. The asymmetry—excusing #49 but keeping #7—was error as to #7.

But Jitnan also requires a prejudice showing: the appellant must show the error resulted in an unfair or partial juror serving. Because Cooper did not timely and meaningfully develop that prejudice argument (and raised it primarily in reply), waiver principles under Khoury v. Seastrand defeated relief.

3) Attorney misconduct: misconduct found, but cure/harmlessness credited

The Supreme Court condemned three highlighted incidents as misconduct, invoking NRPC 3.4(e)’s bar on alluding to inadmissible matters: (i) references to excluded “recreation” evidence, (ii) “What are you trying to hide?” insinuations after objections, and (iii) the attempt to elicit in front of the jury that Cooper “would have a problem” with the jury seeing an excluded/limited video “in full context.”

Even so, the remedy question was governed by Lioce v. Cohen: where objections were sustained and admonitions given, the appellant must show the conduct was so extreme it could not be cured. The Supreme Court deferred to the trial judge’s superior vantage point and emphasized the trial’s scale (“volumes of evidence” over 23 days) and the verdict’s structure (no negligence found, so damages-focused credibility attacks had diminished appellate significance). The court also treated the large quantity of admitted social media material (“over 800 admissible social media posts”) as diluting any incremental effect of a few additional videos.

4) Late insurance disclosure: violation without articulated trial prejudice

Xpertes should have disclosed the excess policy earlier under NRCP 16.1(a)(1)(A)(v). But the Supreme Court treated the issue as forfeited/insufficiently argued for new-trial relief: Cooper did not supply authority linking the violation to the remedy sought and did not concretely explain prejudice beyond generalized “different strategy” assertions.

5) Undisclosed impeachment videos: the court identified a procedural abuse but found it non-prejudicial

The most jurisprudentially notable portion of the order is the court’s treatment of the impeachment videos. Although it accepted that impeachment evidence is often admissible and that nondisclosure alone is not automatically reversible, the court held it was an abuse of discretion to permit undisclosed video use in a “compromised manner” that signaled to the jury that “allegedly damaging evidence” existed but could not be viewed—precisely the “mystique and curiosity” concern identified in Coe v. Centeno-Alvares.

Nonetheless, the error was deemed harmless given: (i) the trial’s length and breadth, (ii) the presence of abundant other impeachment/social media evidence, and (iii) the jury’s threshold finding of no negligence (meaning even a successful damages-credibility attack did not logically explain the liability verdict). This is a practical application of Nevada’s prejudice requirement: even acknowledged trial-management errors do not yield a new trial without a record-based showing that the verdict might have differed.

6) Expert impeachment and scope

The Supreme Court rejected broad claims that defense questioning strayed beyond expert scope because Cooper did not show prejudice in a cogent way and many objections were sustained. On the more developed issue—impeachment of Dr. Fazzini with an undisclosed settlement—the court relied on Hill v. Parker to uphold impeachment with undisclosed public materials relevant to credibility.

7) Spoliation instruction: no entitlement to fact-specific adverse inference

Even though Cooper sought a fact-specific adverse inference due to the booth being disassembled and sold after her preservation letter, the Supreme Court emphasized instruction-setting discretion under Bass-Davis v. Davis and read Banks ex rel. Banks v. Sunrise Hospital as permissive rather than mandatory. The district court offered a generic spoliation instruction; Cooper declined it after her preferred version was rejected. The Supreme Court found no instructional error requiring reversal, and in any event no “miscarriage of justice” under Carver v. El-Sabawi as clarified by Cook v. Sunrise Hosp. & Med. Ctr., LLC.

C. Impact

• Practical guidance on impeachment videos: The decision flags a concrete risk: procedures that let jurors infer the existence of excluded “damaging” videos (while not seeing them) can be an abuse of discretion because they invite speculation (“mystique”). Trial courts and litigants should prefer either (i) showing the video to the jury with proper foundation and disclosure, or (ii) excluding it without theatrics that telegraph its supposed impact.
• Misconduct is not self-executing: Even where counsel violates NRPC 3.4(e), appellants must still connect the misconduct to verdict-altering prejudice under Lioce v. Cohen and NRCP 59’s “substantial rights” requirement.
• For-cause challenges require appellate prejudice proof: The case reinforces the Jitnan prejudice requirement and illustrates how waiver (raising prejudice late) can be dispositive even when the underlying juror-bias ruling was erroneous.
• Disclosure violations demand specific prejudice showings: The court treated late insurance disclosure and several evidentiary complaints as non-starters absent record-cited, outcome-linked prejudice and supporting authority.
• Spoliation instructions remain discretionary: Parties should not assume entitlement to fact-specific adverse inferences; Banks remains fact-bound and “narrowly construed.”

4. Complex Concepts Simplified

• Batson challenge: A three-step process to test whether a peremptory strike was racially motivated: (1) inference of discrimination, (2) race-neutral reason, (3) judge decides if the reason is pretext and discrimination occurred.
• For-cause challenge: A request to remove a juror because bias (or other disqualifying reason) means the juror cannot be fair. Even if a judge wrongly denies it, a new trial typically requires showing that a biased juror actually sat and affected the fairness of the trial.
• Spoliation / adverse inference: If a party destroys or fails to preserve evidence, a court may instruct jurors they may infer the missing evidence would have been unfavorable to that party. Nevada courts have discretion over the wording and whether it is fact-specific.
• Harmless error: A mistake occurred, but it likely did not change the result. Appellate courts generally will not reverse unless the error materially affected substantial rights.
• “Trial by ambush”: Unfair surprise at trial from undisclosed evidence. Nevada courts balance the need for orderly disclosure against whether the surprise actually prejudiced the opponent and whether bad faith is present.

5. Conclusion

Cooper v. Xpertes, LLC is an affirmance anchored in prejudice discipline: even where the Supreme Court identified real trial-level problems—most notably counsel misconduct under NRPC 3.4(e), a for-cause error, and an abuse of discretion in how undisclosed impeachment videos were deployed—it declined to order a new trial absent a developed, record-based showing that the outcome might have changed.

The decision’s most instructive contribution is its warning against impeachment-video procedures that create “mystique” by signaling excluded damaging evidence to the jury. Yet it simultaneously underscores that Nevada’s new-trial remedy remains exceptional: appellants must tie errors to substantial-rights prejudice under NRCP 59(a)(1) and the Carver/Cook miscarriage-of-justice framework.