Is There a Duty to Find and Disclose an Opponent’s “Hallucinated Citations”?

In one recent “hallucinated” citation decision, a Court Suggested That Opposing Counsel Also Failed to Check Citations (Apr. 14, 2026).

A recent article, Amanda Robert, “Shared Responsibility” (ABA Journal Fall 2026), 19, states that “Judges are increasingly faulting lawyers who fail to point out AI-generated fake citations in their opponent’s filings.”  The article states that one court wrote that it “should not be left as the last line of defense against citations to fictional cases in briefs.” [citation omitted].

However, Ms. Robert quotes an attorney who states that the Model Rules of Professional Conduct that justify sanctions against the citing attorney, do not apply to an attorney who has not signed the filing.  This difference has led to a different result.

Ms. Robert states that “[i]n at least two cases, judges refused to award attorney fees or grant relief to counsel who didn’t bring AI-induced errors to their attention.” She reports that courts have used “increasingly ‘stronger language’” in admonishing “non-offending counsel.” [citation omitted].

One attorney is quoted as stating: “This is requiring counsel to continue to respond to all arguments in all cases, and by dong that, you should be able to identify cases that just don’t exist at all….”

See generally, Litigant Forfeited Claim that Court Erred by Relying on Hallucinated/Fictional Cases(Mar. 11, 2026).