Obligation to “Cite-Check … the Cases Cited by the Other Side” and Report Errors to Court

From Nuvola, LLC v. Wright, decided Nov. 21 by Hennepin County (Minn.) Judge Laurie Miller:

For the reasons the Court has outlined above, the Court finds Mr. Knaak’s failure to check the legal authority cited in his brief and his reliance on non-existent case law in his advocacy before this Court raises a question as to whether he breached his duty of competence to Ms. Wright. The Court will refer Mr. Knaak to the Office of Lawyer’s Professional Responsibility (OLPR) for appropriate action. Any mitigating factors proffered by Mr. Knaak, including his compliance with his obligation to educate other lawyers about this issue under this Order, may be relevant to a future ethics investigation and any subsequent recommendations by the OLPR, but the Court will not analyze them here as the Court does not make explicit findings on or enforce ethics rules.

The Court also finds troubling Mr. Braun’s [i.e., opposing counsel’s] failure to identify or bring the non-existent case citations to the Court’s attention before the hearing on the motion to compel arbitration. TheCourt should not be left as the last line of defense against citations to fictional cases in briefs filed with the court.

While Mr. Braun did not create or rely on the fake citations, he also did not detect them. Instead, he admitted he did not review the cases cited by his opponent. If he had checked out the citations in the brief to which he was responding, he no doubt would have brought the issue to the Court’s attention by the time of the motion hearing, and that would have allowed the Court to take the non-existence of the cited cases into consideration as it heard the argument on the merits of Defendant’s motion to compel arbitration, instead of leaving the Court to discover that issue on its own, after the hearing was concluded.

The Court does not find Mr. Braun’s conduct to be sanctionable, as he did not cite any non-existent cases to the Court. [Nonetheless], the Court reminds counsel that it is the obligation of counsel on both sides to respond to each other’s arguments, including completing a basic cite-check of the cases cited by the other side.

The Court urges all lawyers to take seriously their obligation to ensure that the legal arguments being made and considered by theCourt rest upon good law, not fictional cases dreamed up by a computer. The development of the common law relies upon the accurate citation of existing caselaw, as lawyers and courts analyze new disputes. Infection of the body of caselaw by fake Al-generated citations threatens the integrity of the common law.

The court earlier in the opinion noted (focusing Mr. Knaak’s failure to check his own work) that:

Westlaw now provides a tool called “Quick Check” that allows a user to upload a lawyer’s own work or the work of an adverse party and quickly identify a list of authorities cited. The Court did not use this tool to discover the non-existent citations, and does not endorse it as a substitute for traditional citation checks. The Court followed the old-fashioned process of looking up the key cases cited by the lawyers, to read them and decide whether it agreed with the parties’ reading of pertinent caselaw. However, to the extent a lawyer may wish to conduct a faster citation-check process, the availability of the “Quick Check” tool demonstrates that the investigation required of a lawyer by Rule 11 can be accomplished efficiently through readily available methods.

Judge Sharion Aycock (N.D. Miss.) reached a similar conclusion last month in Billups v. Louisville Municipal School Dist.:

The Court also observes that the Defendant … could have flagged the fictious citation and misrepresentation of case law [by Plaintiff’s counsel] in a reply brief or supplemental filing. The Court takes this opportunity to issue a charge. Going forward, the Court expects all parties to assist in maintaining the integrity of the judicial process and to be diligent in flagging AI misuse. “[O]therwise, the risk is too great that such errors will persist undetected, potentially leading to an outcome unsupported by law.” Elizondo v. City of Laredo (S.D. Tex. 2025).

Judge Marina Garcia Marmolejo’s order in Elizondo does indeed take the same view:

The Court also observes that Defendant, the City of Laredo, could have flagged these fictitious citations in a reply brief or supplemental filing. Although this oversight does not rise to the level of sanctionable conduct, the Court expects all parties to assist in maintaining the integrity of the judicial process by alerting the Court to such errors. The Court encourages greater diligence in flagging citation errors in the future—otherwise, the risk is too great that such errors will persist undetected, potentially leading to an outcome unsupported by law.

As I noted last month when I discussed these last two cases, lawyers often need no prompting to alert the court to errors by the other side. But sometimes they might feel reluctant to look like they’re piling on with objections, especially when the erroneous citation is on a tangential point, or when they think they’ve already destroyed the other side’s arguments on the merits. And sometimes they might be reluctant to spend their time and the client’s money on putting together a list of errors by the other side (especially when that requires a whole new supplemental filing). Indeed, even searching for those errors using a tool such as Westlaw’s, though not that difficult, does take at least some time and money, especially since one needs to not just run the tool but closely analyze any errors it claims to find.

But these decisions—whether you think they’re right or wrong—show that checking the other side’s filings for hallucinations, and alerting the court to them, may be important to maintaining the court’s confidence and goodwill. The decisions can be useful citations if you do want to file such a list of errors but are afraid that a different judge will fault you for piling on. And they can be worth noting to your client if you want to explain why you’re spending time and money on listing (and verifying and explaining) the other side’s errors.