Conclusory (False?) Accusations of Using False Case Citations Are Sanctionable
“Hallucinations” by West and Lexis AI? A Cautionary Study and Cautions About the Study
April 11, 2026Court Suggests That Opposing Counsel Also Failed to Check Citations
April 14, 2026
Decisions involving the use of “hallucinated” or fictitious case citations are blooming like flowers in spring. Show cause orders, reprimands, admonishments, or sanctions often follow an allegation that an opponent relied on nonexistent “authority.”
But allegations of misuse of artificial intelligence should not be lightly made. Vigorous advocacy is markedly different:
In his opposition brief, Walsh again accuses Rokoko’s counsel of using Artificial Intelligence (“AI”)-hallucinated case law…. His allegations are unsubstantiated and without merit. The Court has found no instance where Rokoko’s counsel cites to nonexistent case law. While Walsh may disagree with Rokoko’s counsel about what a case stands for or the weight it carries, these are not grounds for accusing opposing counsel of citing AI-hallucinated case law. These allegations are especially concerning as the Court is aware of the damage that using, or simply being accused of using, AI-hallucinated case law can have on an attorney’s career. The Court warns Walsh that if he continues to make baseless allegations of this kind, the Court will exercise its inherent authority to impose sanctions for bad-faith conduct….
Walsh v. Rokoko Electronics, 2026 WL 970227, at n. 5 (C.D. Cal. Apr. 9, 2026)(emphasis added).
