AI Hallucination Cases

In his response, Counsel acknowledged that he first researched relevant cases, and then "entered the cases into ChatGPT and requested that it highlight favorable arguments contained in the list of cases."

Plaintiff's opposition brief cited numerous nonexistent cases. Defendant identified the fabricated citations in its reply; plaintiff admitted reliance on an AI-based drafting tool and apologized. The court confirmed several cited cases do not exist but declined to pursue Rule 11 sanctions, finding apology, mitigation, and proportionality concerns.

The Court identified multiple instances where counsel cited nonexistent cases and misquoted Cal. Civ. Code § 988(c). The Court admonished counsel, noted corrections in later briefing, and declined to credit the arguments based on the erroneous citations. No sanctions were imposed.

Morehouse replied that Warfield's filings relied on incorrect and nonexistent case citations; the Court noted that allegation but did not impose sanctions and dismissed the case for lack of personal jurisdiction.

The court identified that Plaintiff relied on a nonexistent case citation and noted the citation had been previously flagged in the record.

Rather amazingly, plaintiff asked and was granted leave to file a "Case Law Verification Index" that contained further hallucinations.

Relator admitted her petition contained citation errors and hallucinated cases after relying on inadequate assistance; court denied leave to amend and dismissed the writs.

Order to show cause is here. Counsel was eventually ordered to pay 10,000 USD to opposing counsel (see here).

Debtor cited a case the court could not locate; the court noted the citation appears incorrect and may be an AI "hallucination," and referenced other decisions sanctioning reliance on fabricated AI-generated cases.

In an earlier Report and Reccomendations, the court found that significant portions of the plaintiff's filings copied from an AI program included citations to cases that could not be identified in Westlaw and an apparent AI-generated medical report; the court struck the filings and instructed compliance with Rule 11 and practice standards.

The court observed that Mother's briefs included many cited authorities that do not exist and that one statute she cited was not on point. Mother admitted using Chat GPT to prepare pleadings. The court affirmed the trial court's orders and warned litigants to verify AI-generated citations.

Party later filed for reconsideration, arguing that the judge had been biased; this failed (see here).

Lawyer later explained that he had "used Microsoft’s Copilot for its editing functions in an effort to review and improve the draft document by fixing grammar, spelling, and improving badly phrased sentences" - not for legal research.

On November 12, 2025, the court resolved the Show Cause proceedings without formal sanctions.

" Moreover, we take this opportunity to caution practitioners of this Commonwealth on the submission of briefs or citations without confirming their accuracy and the correctness of the resulting analysis. The abject failure to conduct due diligence when making arguments to the Court greatly impacts the profession and undermines confidence in the skills and knowledge necessary to practice as an attorney. Failure to verify substantive legal citations prior to submission to this Court is not only in derogation of the RAP, but also violates the attorney's ethical responsibilities. See Supreme Court Rule 3.130(1.1).

Mistakes occur. Oversights happen. Those types of inadvertent errors we could absolve. However, purposelessly submitting a brief to a Court of law without confirming that the cited case law even exists is an affront to the dignity of the Court system, the legal profession as a whole, the judiciary, the client, and the public at large."

The Board found over 70% of citations in Huffman's reply brief inaccurate, including fabricated cases, misattributed reporter citations, cases that did not support cited propositions, and incorrect or non-existent transcript/Rule 4 citations. Counsel admitted using AI to generate portions of the brief. The Board treated the motion as one for Rule 11-type sanctions and struck the reply brief; it emphasized attorneys' duty to verify AI-generated content.