The Lawletter Vol. 50 No. 4
Jason Holder—Senior Attorney
ATTORNEY ETHICS: How to Make a Bad Situation Worse: Court Sanctions Attorney for Using Hallucinated Cases to Defend Himself Against Motion Alleging Prior Use of Hallucinated Cases
In a cautionary tale for attorneys seeking to use artificial intelligence (“AI”) technology in an effort to save time and money, a New York trial court has sanctioned counsel for relying “upon unvetted AI—in his telling, via inadequately supervised colleagues—to defend his use of unvetted AI.” Ader v. Ader, 2025 N.Y. Misc. LEXIS 7848, at *1, 2025 NY Slip Op 51563(U), 1, 87 Misc. 3d 1213(A), 240 N.Y.S.3d 701 (Sup. Ct. N.Y. County Oct. 1, 2025). The initial offense was brought to the court’s attention when the opposition “identified inaccurate citations and quotations in Defendants' opposition brief that appeared to be ‘hallucinated’ by an AI tool.” Id. at *3. Without admitting or denying the use of AI, the offending attorney initially suggested that the passages cited by the opposition “were intended as paraphrases or summarized statements of the legal principles established in the cited authorities.” Id. Rejecting this argument, the court noted that the “paraphrases” included “bracketed terms to indicate departure from a quotation (not something one would expect to see in an intended paraphrase) and comments such as ‘citation omitted.’” Id. at *4. Compounding matters, the cases cited relied upon for the alleged paraphrases of law “did not stand for the propositions quoted, were completely unrelated in subject matter, and in one instance did not exist at all.” Id.
The court was equally troubled by the seeming use of fake citations and quotations to support uncontroversial, correct statements of law. Id. Describing this practice as “no less frivolous” than fabricated case law in support of contested statements of law, the court explained that “when a fake case is used to support an uncontroversial statement of law, opposing counsel and courts—which rely on the candor and veracity of counsel—in many instances would have no reason to doubt that the case exists.” Id. As a result, the fake case may make its way into a judicial opinion, which itself would then be relied upon by subsequent courts resulting in the proliferation of the hallucinated citations. Id. at *4-5 (“The proliferation of unvetted AI use thus creates the risk that a fake citation may make its way into a judicial decision, forcing courts to expend their limited time and resources to avoid such a result.”).
Faced with a motion for sanctions for the repeated use of unvetted AI in the summary judgment opposition, counsel bafflingly submitted an opposition to sanctions containing “another wave of fake citations and quotations,” id. at *5, including “more than double the number of mis-cites, including four citations that do not exist, seven quotations that do not exist in the cited cases, and three that do not support the propositions for which they are offered.” Id. (emphasis in original). While counsel initially denied using unvetted AI in its motion oppositions, he was ultimately forced to admit that he had used AI and missed the references to false citations. Id. at *6-7. Explaining how this could have happened in his opposition to sanctions, the attorney indicated that he reviewed the response as of minimal importance “relative to the other time-sensitive tasks on which he and his recently hired staff were working at the time.” Id. at *7.
Admonishing counsel, the court was careful to note that the use of AI is not the problem per se; instead, “[t]he problem arises when attorneys abdicate their responsibility to ensure their factual and legal representations to the Court—even if originally sourced from AI—are accurate.” Id. at *10-11. By failing to check their work, regardless of the tool used to create it, attorneys “prejudice their clients and do a disservice to the Court and the profession.” Id. at *11. “In sum, counsel's duty of candor to the Court cannot be delegated to a software program.” Id. Ultimately, the court awarded reasonable costs and fees incurred responding to the offending filings with the sanction applying to “both Defendants and their counsel, jointly and severally.” Id. at *12. The court also directed that a copy of the decision and order be sent to “Grievance Committee for the Appellate Division, First Department and the New Jersey Office of Attorney Ethics.” Id.
