What was hallucinated

Fabricated: Case Law | Williamson cited numerous nonexistent cases in his filings; opposing parties flagged many citations as to non-existent authorities and the magistrate judge found these citations to be willful misuse. || Misrepresented: Case Law | Williamson misstated and misrepresented case holdings to make them support his position; the magistrate judge characterized these misrepresentations as egregious and willful. || False Quotes: Case Law | Williamson misquoted existing cases in filings; the magistrate judge found misquotations and noted they were used to support his claims.

Sanction teardown · 11th Cir. CA, USA · 2026-05-04

Eliott Williamson v. TransUnion LLC, Experian Information Solutions, Inc.

What happened

In 11th Cir. CA, 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)

Williamson cited numerous nonexistent cases in his filings; opposing parties flagged many citations as to non-existent authorities and the magistrate judge found these citations to be willful misuse.
Misrepresented (Case Law)

Williamson misstated and misrepresented case holdings to make them support his position; the magistrate judge characterized these misrepresentations as egregious and willful.
False Quotes (Case Law)

Williamson misquoted existing cases in filings; the magistrate judge found misquotations and noted they were used to support his claims.

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

Affirmed on appeal earlier dismissal with prejudice

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/2116/Williamson_v._Transunion_USA_4_May_2026.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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