Just on One Day—Last Friday—Six Courts Issued Opinions Noting Fake Cites or Quotes in Briefing
Four were state appellate courts and two were district courts. Four involved filings by lawyers, and two by self-represented litigants. All seem likely to have been the result of unchecked use of AI, though I suppose it's possible that there was no AI and the error just came directly from a human.
If you want case names, they are Prososki v. Regan (Neb.), Gentry v. Thompson (E.D. La.), Blair v. Sanctuary Bluff Homeowners Ass'n, Inc. (Ky. Ct. App.), Hessert v. Hessert (Fla. Ct. App.), State v. Coleman (Ohio Ct. App.), and Lopez v. Mead Johnson Nutrition Co. (N.D. Cal.). The hits just keep coming.
And of course many such hallucinated materials aren't spotted by courts, are spotted but not remarked on, or are spotted and remarked on but don't make their way onto Westlaw, where a query I have picks them up. (Most state trial court decisions don't result in any detailed written order, but instead offer just a bottom-line result; and even those that are written often don't get posted on Westlaw.)