Lawyers Sanctioned for AI-Fabricated Case Citations

Mata v. Avianca, Inc. was an ordinary personal injury suit in the Southern District of New York: a passenger said a metal serving cart struck his knee on a 2019 flight. When Avianca moved to dismiss, the plaintiff's opposition cited decisions, including one styled Varghese v. China Southern Airlines, that did not exist. Neither opposing counsel nor the court could find them. The lawyer who did the research, Steven Schwartz, had used ChatGPT, believed it worked like a search engine, and asked it to confirm the cases were real, which it did. His colleague Peter LoDuca signed the filings. When the court ordered them to produce the decisions, they submitted AI-generated text presented as opinions. On June 22, 2023, Judge P. Kevin Castel imposed a $5,000 penalty on the two lawyers and their firm under Rule 11 and ordered them to write to their client and to each real judge falsely named as an author. The court made clear that using AI was not the problem. The lawyers failed by abandoning their responsibilities and continuing to stand by the fake cases after they were questioned. Later cases show the pattern persisting. The Second Circuit in Park v. Kim (2024) referred an attorney for possible discipline. In United States v. Cohen, Bard-generated citations reached a filing, though the judge declined sanctions. In Wadsworth v. Walmart (2025), lawyers were sanctioned over citations from their firm's in-house AI tool, showing that internal or legal-specific tools are not immune. Some judges, including Judge Brantley Starr of the Northern District of Texas in 2023, now require certifications about AI use. The central misconception is that asking the AI to double-check itself counts as verification. It does not. A model asked whether a case exists will often generate a confident yes. Verification means retrieving the actual opinion from an authoritative source and reading it.