Footnote in opinion warns counsel not to cite AI-generated fake cases again

A federal judge in Wisconsin suspected that one of the parties appearing before the court had used generative AI to write a brief, which resulted in a hallucinated case. The judge issued an opinion with this footnote:

Although it does not ultimately affect the Court’s analysis or disposition, Plaintiffs in their reply cite to a case that none of the Court’s staff were able to locate. ECF No. 32 at 5 (“Caserage Tech Corp. v. Caserage Labs, Inc., 972 F.3d 799, 803 (7th Cir. 1992) (The District Court correctly found the parties agreed to permit shareholder rights when one party stated to the other its understanding that a settlement agreement included shareholder rights, and the other party did not say anything to repudiate that understanding.).”). The citation goes to a case of a different name, from a different year, and from a different circuit. Court staff also could not locate the case by searching, either on Google or in legal databases, the case name provided in conjunction with the purported publication year. If this is, as the Court suspects, an instance of provision of falsified case authority derived from artificial intelligence, Plaintiffs’ counsel is on notice that any future instance of the presentation of nonexistent case authority will result in sanctions.

One must hope this friendly warning will be taken seriously.

Plumbers & Gasfitters Union Local No. 75 Health Fund v. Morris Plumbing, LLC, 2024 WL 1675010 (E.D. Wisconsin April 18, 2024)