One fake citation can turn into a real disciplinary problem.
The Case That Put AI Hallucinations on the Map: Mata v. Avianca
In June 2023, Judge P. Kevin Castel of the U.S. District Court for the Southern District of New York sanctioned two attorneys and their law firm for submitting a court filing that contained fabricated judicial opinions and citations generated by ChatGPT.
What happened: Attorney Steven A. Schwartz used ChatGPT to research legal precedents for a motion opposing Avianca’s request to dismiss a personal injury case. ChatGPT generated a list of cases that looked real—complete with case names, citations, quotes, and internal citations. Schwartz did not verify them. He even asked ChatGPT if the cases were real, and the chatbot reassured him they were.
They were not. The cases did not exist. The quotes were fabricated. The internal citations were fake.
When opposing counsel and the court questioned the cases, Schwartz and co-counsel Peter LoDuca continued to stand by them, submitting additional affidavits that included copies of the “decisions”—which ChatGPT had also fabricated. Only after repeated court orders did they admit the truth.
The sanctions:
- A $5,000 fine, imposed jointly and severally on the two attorneys and their law firm.
- A requirement to notify the judges who were falsely identified as authors of the fake opinions.
- A requirement to notify the client of the misconduct.
- Public reprimand and reputational damage.
Why This Matters: The Harm Is Not Just Embarrassment
The court was clear: the harm from fake citations is not just wasted time or embarrassment. It undermines the integrity of judicial proceedings.
Judge Castel wrote:
“Many harms flow from the submission of fake opinions. The opposing party wastes time and money in exposing the deception. The Court’s time is taken from other matters. The client is not well served. And the use of nonexistent judicial opinions may constitute forgery, and presents a fraud upon the court.”
The sanctions included bad-faith findings. The court held that the attorneys had consciously avoided obvious red flags, and that their false statements to the court compounded the misconduct.
The Lesson: AI Hallucinations Are Not Hypothetical
AI systems—including ChatGPT, Claude, and other large language models—can “hallucinate”: they generate content that looks plausible but is factually incorrect. This includes:
- Fake case citations
- Fabricated quotes from real cases
- Invented statutes or regulations
- Plausible-sounding but incorrect legal rules
The problem: These hallucinations can be confident and detailed. They can include case numbers, court names, dates, and internal citations. They can look real.
The rule: Using AI for legal research is not inherently improper. But attorneys have an affirmative, non-delegable duty to verify the accuracy of all filings, regardless of the tool used. Rule 11 of the Federal Rules of Civil Procedure requires that every filing be supported by a reasonable inquiry into the facts and law. Delegating that inquiry to an AI—without verification—is not reasonable.
What This Means for Boards and Executives
If your organization uses AI for legal research, contract drafting, compliance work, or policy analysis, you need verification controls.
Three questions for oversight:
- Who is using AI for legal or compliance work? Do they understand that AI can hallucinate?
- What is our verification workflow? Before any AI-assisted filing, brief, contract, or policy is finalized, who checks it? How?
- What happens if we get it wrong? Have we thought through the consequences—sanctions, reputational damage, client notification, regulatory scrutiny?
What verification workflow do you use before filing anything AI-assisted? I deliver board-level courses and consult on AI governance, legal risk, and verification controls. Contact me.
Relevant Sources
- Mata v. Avianca, Inc., No. 1:2022cv01461, Opinion and Order on Sanctions (S.D.N.Y. June 22, 2023) — U.S. District Court, Southern District of New York — https://www.nhd.uscourts.gov/sites/default/files/pdf/Mata-v-Avianca-sanctions-order.PDF
- Mata v. Avianca, Inc. — Wikipedia — https://en.wikipedia.org/wiki/Mata_v._Avianca,_Inc.
- Practical Lessons from the Attorney AI Missteps in Mata v. Avianca — Association of Corporate Counsel — https://www.acc.com/resource-library/practical-lessons-attorney-ai-missteps-mata-v-avianca
- Mata v. Avianca, Inc., 678 F. Supp. 3d 443 — Justia — https://law.justia.com/cases/federal/district-courts/new-york/nysdce/1:2022cv01461/575368/54/
- Use of Generative AI in the Law: Lessons from Two Federal Cases — American Bar Association — https://www.americanbar.org/groups/litigation/resources/newsletters/privacy-data-security/generative-ai-in-the-law/