For more on the underlying errors in the plaintiffs' brief, see here. An excerpt from yesterday's sanctions order, in Puerto Rico Soccer League NFP, Corp. v. Federacion Puertorriquena de Futbol:
Plaintiffs' motions included at least fifty-five defective citations, requiring hours of work on the Court's end to check the accuracy of each citation. Plaintiffs' counsel never offered a satisfactory explanation for why their citations in multiple motions were so severely flawed. Plaintiffs denied using generative artificial intelligence. But the sheer number of inaccurate or nonexistent citations suggests otherwise. And in any event, the violations of Fed. R. Civ. P. 11 and applicable ethical rules occurred regardless of whether they were caused by misuse of generative artificial intelligence or other means. This behavior stands in contrast to several of the cases [that imposed much lower sanctions], where various attorneys facing sanctions offered an explanation as to how they erred.
Defendants actually asked for $60K in compensation for the attorney fees and research costs expended to deal with the incorrect citations, but the court reduced that by 60%:
