The most striking example is LNU v. Blanche, Ninth Circuit, June 3, 2026.

Attorneys Mike Singh Sethi and William Rounds submitted briefs containing:

nonexistent cases;
misattributed quotations;
grossly misrepresented real cases.

They repeatedly denied that AI might have caused the errors.

The Ninth Circuit had specifically considered whether they should be sanctioned, suspended or disbarred from practice before that court.

It ultimately imposed:

$2,500 each in personal sanctions;
six-month suspension from practice before the Ninth Circuit;
mandatory notification to clients, opposing counsel and judges;
a two-year requirement that future filings disclose AI use and certify that citations and quotations have been personally reviewed;
referral to the State Bar of California and other applicable licensing authorities.

This is extremely important.

The court explicitly said it was not punishing AI use itself.

It was punishing:

filing false material and then failing to be candid about it.

That distinction is becoming the central rule of AI legal ethics.

Sources

• U.S. Court of Appeals for the Ninth Circuit — LNU v. Blanche