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HD-INC-002
Legal services · United States · 2023 · Hallucination & fabrication

Mata v. Avianca: A Lawyer Cited Six Fake Cases and Asked ChatGPT to Confirm Them

By Ellie Harris · Filed 1 March 2023

Alleged: Levidow, Levidow & Oberman P.C. developed or deployed the AI system implicated in this incident. Details are drawn from public reports; parties are presumed innocent of any wrongdoing not established by an official finding.

Mata v. Avianca: A Lawyer Cited Six Fake Cases and Asked ChatGPT to Confirm Them

What happened

It was reported that on 27 or 28 August 2019, a passenger was travelling overnight from El Salvador to New York on an Avianca flight when a metal serving cart struck his knee. In 2022, he sued the airline in the United States District Court for the Southern District of New York, but Avianca argued that he had brought the claim too late under the Montreal Convention, an international treaty governing airline liability.

To challenge the airline’s argument, his lawyer, an experienced personal injury attorney with more than thirty years of practice, submitted a filing in March 2023 citing six federal court decisions that appeared to support his position. The cases included Varghese v. China Southern Airlines, Martinez v. Delta Airlines, Shaboon v. EgyptAir, Petersen v. Iran Air, Estate of Durden v. KLM Royal Dutch Airlines and Miller v. United Airlines.

When Avianca’s lawyers tried to locate the decisions, they could not find them. Court staff encountered the same problem, and it eventually emerged that the passenger’s lawyer had used ChatGPT to conduct his research. Rather than checking the citations against a legal database, he had asked ChatGPT whether the cases were genuine, and the system assured him that they were. None of the six cases existed.

On 22 June 2023, the judge imposed sanctions on the lawyer, another lawyer who had signed the filing, and their firm, Levidow, Levidow & Oberman. The second lawyer had not conducted the research and later said he had “no reason to doubt the sincerity” of his colleague’s work, but he had signed the document submitted to the court. The total financial sanction was USD 5,000, and the lawyers were also ordered to send copies of the sanctions decision and the offending filing to their client and to the federal judges whose names had been falsely associated with the fabricated cases.

The lawyer explained that he had not understood ChatGPT could invent legal authorities, believing instead that it operated like a search engine connected to a database of genuine court decisions. The judge rejected that explanation as a defence and found subjective bad faith based on conscious avoidance, concluding that the lawyers had failed to meet their professional obligation to verify the authorities they submitted to court.

What an auditable version would have shown

According to the sanctions decision, the lawyer used ChatGPT to find cases supporting his argument and then returned to the same system when questions arose about whether those cases existed. The problem was that ChatGPT could generate plausible legal citations without retrieving genuine court decisions, and asking it to confirm its own answers provided no independent verification.

The lawyer had mistaken information generated by a language model for information retrieved from a legal source. ChatGPT could produce convincing case names, legal reasoning and quotations, but the appearance of a genuine court decision did not mean that any court had issued it.

An auditable record would have made the distinction between generated and verified information visible throughout the research process. Each citation could have been checked against an independent legal database such as Westlaw, LexisNexis or PACER, with the result recorded alongside the material the lawyer intended to use. A genuine decision would have a verifiable source, while a fabricated citation would fail that check.

The record would also have shown that the lawyer had asked ChatGPT itself to verify the citations rather than consulting an independent source. Had the six cases been checked against an authoritative database before the filing was submitted, their absence could have been identified before they reached the court.

The issue was not simply that ChatGPT produced false information. It was that the information moved from a chatbot into a federal court filing without the verification that legal research requires.

Where the gap was

The court’s decision showed how an established professional responsibility could be overlooked when a new technology was introduced into a familiar task. Lawyers had long used electronic legal databases to locate decisions, read judgments and verify citations, but the passenger’s lawyer treated ChatGPT as though it performed the same function.

Unlike a conventional legal research database, a general-purpose language model can generate text that resembles a legal decision without retrieving an actual case. The lawyer did not recognise that distinction, and when Avianca’s lawyers questioned the citations, he returned to the same system for reassurance rather than checking the authorities independently.

Headlights identifies automation bias in the lawyer’s decision to trust ChatGPT even after questions had been raised about the citations. Rather than checking the cases against an independent legal database, he returned to the same system for reassurance and accepted its answers.

The incident also reveals a rules-behaviour gap. Lawyers were already required to verify the authorities they submitted to court, but that responsibility was overlooked when ChatGPT became part of the research process. The professional obligation had not changed, yet the lawyer’s behaviour had.

There was also diffusion of responsibility. The lawyer explained that he had misunderstood ChatGPT’s capabilities, while the judge made clear that responsibility for the filing remained with the lawyers who submitted it.

These are Headlights’ interpretations of the behaviour described in the court record, not findings made by the judge.

Other courts have since encountered legal submissions containing fabricated AI-generated citations, showing that the underlying problem extends beyond this case. The risk arises whenever a professional treats a convincing AI-generated answer as verified information without checking the source.

What governance should have looked like

The sanctions decision made clear that lawyers remain responsible for the accuracy of the authorities they submit to court, regardless of whether artificial intelligence helped prepare the material. A workable governance process would allow AI to assist with identifying potentially relevant cases, while requiring every citation to be verified against an independent, authoritative legal database before it could appear in a final filing.

The important distinction is between suggesting a citation and confirming that it exists. A language model may help a lawyer identify possible authorities, but verification needs to take place outside the model, using a source capable of establishing whether the decision is genuine.

A CitationVerifier could perform that independent check, while a VerificationGate could prevent unverified citations from moving into a final document. A ConductRecord could preserve the citations generated by the system, the sources consulted during verification and the outcome of each check, creating a record of what happened rather than relying on the lawyer’s recollection.

One useful field would be model_consulted_for_verification, recording whether the lawyer had asked the language model itself to confirm a citation. In this case, the field would have shown that ChatGPT was used both to produce the authorities and to provide reassurance that they were genuine, without an independent database check.

These controls would sit alongside ordinary professional review, including mandatory citation verification, clear identification of AI-generated material, compliance with applicable court disclosure requirements and a separate review of legal authorities before filing. The purpose would not be to prevent lawyers from using AI, but to ensure that introducing a new tool did not remove the checks already required of them.

Failure Pattern: a lawyer relied on fabricated legal citations generated by ChatGPT, then asked the same system to confirm they were genuine. The citations were submitted to a federal court without independent verification.

Governance Principle: AI-generated legal authorities must be verified against independent, authoritative sources before they are relied on in court. Professional responsibility remains with the lawyers submitting the material.

The reference implementation of CitationVerifier, VerificationGate and ConductRecord is open source. It lives at github.com/saffronandindia/headlights-oss, Apache 2.0 licensed and free to install. The repository is public now.

Sources

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The record

An auditable system would have produced a signed, tamper-evident record the moment this happened: what the system did, the version that did it, the basis it acted on, and the action taken, and Levidow, Levidow & Oberman P.C. could have produced it on demand.

This is the record the system as deployed did not produce in a signed, auditable form.

What this teaches
Capture what happened when it happens
What the system did, the version that did it, the basis it acted on, and the action taken, recorded at the moment, not reconstructed after.
Sign it, so no one has to trust the record-keeper
A tamper-evident entry. Edit it later and the signature breaks. The record does not ask for the benefit of the doubt.
Make it verifiable by anyone
A court, a regulator, a customer's lawyer can check the record themselves, without taking the company, or us, at our word.

Headlights summarises publicly reported AI incidents. All summaries are independently written, attributed to their original sources, and intended for research and educational purposes. Allegations are identified as such until established through official findings.

This report is based on the sources listed above and reflects information available at the time of review; later developments may not be captured. Where a person is described as charged with or alleged to have done something, that allegation is unproven unless a conviction or a court or regulatory finding is stated. Headlights publishes journalism and commentary, not legal advice.

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