A lawyer used ChatGPT for research. It invented six court cases. He filed them anyway.
Levidow, Levidow & Oberman (law firm) · 2023
What they did
In a routine personal-injury suit against Avianca, attorney Steven Schwartz used ChatGPT to find supporting case law for a brief. It generated six citations complete with plausible case names and quoted opinions — none of which existed.
What happened
When opposing counsel and the court couldn't locate the cases, the lawyers didn't withdraw the brief — they submitted further filings insisting the cases were real, including AI-generated fake "copies" of the fictional opinions. Judge P. Kevin Castel sanctioned Schwartz, a colleague, and their firm $5,000 for violating Rule 11's duty to verify citations, in what became the watershed case for AI hallucination in legal practice.
The so-what
The hallucination wasn't the expensive mistake — a fabricated citation caught before filing costs nothing. The expensive mistake was trusting the tool's confidence over a five-minute manual check, twice, even after being directly challenged on it.