A federal judge in California has sanctioned a prominent plaintiffs’ law firm after artificial intelligence–generated errors appeared in court filings tied to a lawsuit involving OnlyFans and its parent company.
According to Reuters, U.S. District Judge Fred Slaughter of the Central District of California ordered Seattle-based Hagens Berman Sobol Shapiro and firm partner Robert Carey to pay $10,000 in sanctions after determining that multiple briefs contained legal material that was not supported by existing law. The judge also imposed a separate $3,000 sanction on co-counsel Celeste Boyd.
The ruling stemmed from four briefs filed in a case brought by OnlyFans users against Fenix International Ltd., which alleged that subscribers were unknowingly communicating with paid “chatters” impersonating creators to drive higher spending on the platform.
Judge Slaughter found that portions of the filings relied on fabricated or “hallucinated” legal citations generated through AI tools.
In his order, the judge said the filings violated rules requiring that arguments submitted to the court be “warranted by existing law.” He further noted that even if firm leadership was unaware of how the errors entered the briefs, there was still a duty to supervise co-counsel and ensure compliance with professional standards.
Boyd previously acknowledged in an August declaration that she used OpenAI’s ChatGPT to draft and edit sections of the briefs but failed to independently verify the output. She cited personal issues at the time and said she did not follow her own internal protocols for AI use.
Carey disputed that Hagens Berman itself used artificial intelligence in preparing the filings. He said the problematic citations were introduced by outside co-counsel “without adherence to Hagens Berman’s AI protocols,” adding that the firm’s management committee is reviewing its internal processes.
Judge Slaughter also rejected a request from the plaintiffs’ lawyers to withdraw and correct the AI-affected briefs. He wrote that allowing revisions would unfairly burden defendants who had already responded, noting that the proposed corrections still contained errors.
Separately, the judge granted motions to dismiss filed by Fenix International and its affiliated agencies, while allowing plaintiffs to amend their complaint.