Amtrust North America o/b/o Justin McGinness v. Liberty Mutual Insurance Company
Superior Court of New Jersey, Appellate Division · N.J. Super. Ct. App. Div. · New Jersey bar guidance
Verified April 26, 2026
- Citation
- Amtrust N. Am. o/b/o McGinness v. Liberty Mut. Ins. Co., No. A-2587-24, 2026 N.J. Super. Unpub. LEXIS 633 (App. Div. Mar. 27, 2026)
- Decided
- March 27, 2026
Summary
Plaintiff's appellate counsel Nicholas W. Mattiacci of N.W. Mattiacci Law, LLC cited four nonexistent New Jersey cases in his merits brief on a workers' compensation UIM subrogation appeal, including a fabricated "Aetna Cas. & Sur. Co. v. Hanna, 224 N.J. Super. 462 (App. Div. 1988)." When defense counsel flagged the missing "Aetna" citation in the opposition brief, Mattiacci's reply brief insisted "a review of legal databases confirms the existence of a case involving a New Jersey Appellate Division opinion with a similar citation" rather than retract the citation. The per curiam panel (Judges Currier and Berdote Byrne) found the nonexistent cases were "hallmarks of generative artificial intelligence" and that counsel's failure to retract after notice violated RPC 3.3, Rule 2:9-9, and Rule 1:4-8.
- AI tool:
- Unspecified generative AI
- Sanction amount:
- $1,000
What sanction did the court impose?
$1,000 sanction imposed personally on plaintiff's counsel, payable to the Treasurer of the State of New Jersey within thirty days, with proof of payment to the Clerk of the Appellate Division. Trial court dismissal affirmed in part and remanded for entry of a dismissal without prejudice.
Why does Amtrust North America o/b/o Justin McGinness v. Liberty Mutual Insurance Company matter for law firms using AI?
The opinion is notable for the panel’s framing that “[a]ttorneys have a duty of candor to the tribunal that cannot be outsourced to AI,” and for sanctioning the failure to retract as much as the original fabrication. For managing partners, the case underscores that an appellate panel will treat a dismissive reply brief, signed after the adversary has flagged a missing citation, as an independent Rule 1:4-8 and RPC 3.3 violation distinct from the underlying hallucination. New Jersey’s Preliminary AI Guidelines (Jan. 24, 2024) are cited as the operative standard.
Sources
Further reading
Source PDF is a Westlaw printout mirrored from the Damien Charlotin hallucination database. We are working to add the underlying court docket (PACER, CourtListener, or court website) as a second source.