What was hallucinated

Fabricated: Case Law | Defendants flagged numerous fictitious case citations and incorrect case citations in Plaintiffs' response brief; Plaintiffs later filed a Notice of Corrected Citations and the Court noted the issue. || False Quotes: Case Law | Defendants identified non-existent quotations and misquoted case law in Plaintiffs' brief; Plaintiffs filed corrections and the Court reviewed the submissions, declining sanctions.

Details

Defendants' reply identified fictitious cases, incorrect citations, and non-existent quotations in Plaintiffs' response brief. Plaintiffs filed a Notice of Corrected Citations; the Court noted formatting that suggested use of generative AI but declined to sanction the pro se plaintiffs, advising compliance with Rule 11 in future filings.

Sanction teardown · D. South Dakota, USA · 2025-11-17

Mattson & Dostal v. Rosebud Electric Cooperative et al.

What happened

In D. South Dakota, USA, a filing relied on an unnamed/unconfirmed AI tool to help draft legal argument. The court identified the following problems with the citations in that filing:

Fabricated (Case Law)

Defendants flagged numerous fictitious case citations and incorrect case citations in Plaintiffs' response brief; Plaintiffs later filed a Notice of Corrected Citations and the Court noted the issue.
False Quotes (Case Law)

Defendants identified non-existent quotations and misquoted case law in Plaintiffs' brief; Plaintiffs filed corrections and the Court reviewed the submissions, declining sanctions.

Which AI tool

an unnamed/unconfirmed AI tool. Note: Charlotin's public database records tool attribution only where a court order, brief, or reporting on the matter states it explicitly; "unidentified" or "implied" means the record indicates AI use but does not name a specific product — we do not guess.

Outcome

Warning

Additional detail

How Citation Safe would have caught this

Citation Safe runs three deterministic layers before a brief is filed: (1) does the citation exist against CourtListener's database of published opinions, (2) if quoted, does that exact language appear in the source, (3) does the cited case actually support the proposition it is cited for. Fabricated case citations fail Layer 1. Fabricated or misattributed quotations fail Layer 2 even when the underlying case is real. Misrepresented holdings — a real case cited for a proposition it does not support — are the target of Layer 3. None of these checks involve asking another language model whether the citation looks right; they are lookups and text-matches against the actual source, which is why a hallucinated citation has to survive a direct lookup against the authoritative source — not another model's opinion — to earn a VERIFIED stamp; our measured false-verify rate is published live at /quality.

Check a brief before you file it → · See our live false-verify rate

Source: https://www.damiencharlotin.com/documents/1062/Mattson__Dostal_v._Rosebud_USA_17_November_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

Don’t be the next case in this database.

Citation Safe checks every citation against primary sources before it reaches a filing.

Try the free checker Back to database

On the opposing side of their next motion?

Check their next brief through the same engine that would have caught this filing — $49, no signup, full annotated report you can attach to your Rule 11 or sanctions motion.

Open Opposition Check — $49 Sanctions-motion template