What was hallucinated

Fabricated: Case Law | Plaintiff cited Snyder v. City of Sanford, 645 So. 2d 1126 (Fla. 5th DCA 1994), which the Court determined does not exist after its own search and relied on in imposing sanctions. || Fabricated: Case Law | Plaintiff cited Valley Nat’l Bank of Arizona v. A.E. Moses, 617 So. 2d 455 (Fla. 4th DCA 1993), which the Court determined does not exist after its own search and relied on in imposing sanctions.

Details

AI UseAlthough O’Brien denied deliberate fabrication and described the inclusion of fake citations as a “minor clerical error” or “mix-up,” the court rejected this explanation. The opinion notes that the citations had no plausible source in other filings and that the brief exhibited structural traits of AI-generated text. The court explicitly concluded that O’Brien “generated his Reply with the assistance of a generative artificial intelligence program.”Ruling/SanctionThe court dismissed the case with prejudice on dual grounds:The claims should have been raised as compulsory counterclaims in prior pending litigation and were thus procedurally barred under Rule 13(a)O’Brien submitted fake legal citations, failed to acknowledge the issue candidly, violated local rules, and engaged in a pattern of procedural misconduct in this and other related litigation. While monetary sanctions were not imposed, the court granted the motion to strike and ordered dismissal with prejudice as both substantive and disciplinary remedy.Key Judicial ReasoningJudge Melissa Damian found that the fabricated citations and O’Brien’s refusal to admit or correct them constituted bad faith. She referenced multiple prior instances where O’Brien had been warned or sanctioned for similar behavior, and emphasized that while pro se litigants may receive procedural leniency, they are not exempt from ethical or legal standards. Dismissal with prejudice was chosen as a proportionate sanction under the court’s inherent powers.

Sanction teardown · S.D. Florida, USA · 2025-01-10

O’Brien v. Flick and Chamberlain

What happened

In S.D. Florida, 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)

Plaintiff cited Snyder v. City of Sanford, 645 So. 2d 1126 (Fla. 5th DCA 1994), which the Court determined does not exist after its own search and relied on in imposing sanctions.
Fabricated (Case Law)

Plaintiff cited Valley Nat’l Bank of Arizona v. A.E. Moses, 617 So. 2d 455 (Fla. 4th DCA 1993), which the Court determined does not exist after its own search and relied on in imposing 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

Case dismissed with prejudice, inter alia for use of fake citations and misrepresentations

Additional detail

AI UseAlthough O’Brien denied deliberate fabrication and described the inclusion of fake citations as a “minor clerical error” or “mix-up,” the court rejected this explanation. The opinion notes that the citations had no plausible source in other filings and that the brief exhibited structural traits of AI-generated text. The court explicitly concluded that O’Brien “generated his Reply with the assistance of a generative artificial intelligence program.”Ruling/SanctionThe court dismissed the case with prejudice on dual grounds:The claims should have been raised as compulsory counterclaims in prior pending litigation and were thus procedurally barred under Rule 13(a)O’Brien submitted fake legal citations, failed to acknowledge the issue candidly, violated local rules, and engaged in a pattern of procedural misconduct in this and other related litigation. While monetary sanctions were not imposed, the court granted the motion to strike and ordered dismissal with prejudice as both substantive and disciplinary remedy.Key Judicial ReasoningJudge Melissa Damian found that the fabricated citations and O’Brien’s refusal to admit or correct them constituted bad faith. She referenced multiple prior instances where O’Brien had been warned or sanctioned for similar behavior, and emphasized that while pro se litigants may receive procedural leniency, they are not exempt from ethical or legal standards. Dismissal with prejudice was chosen as a proportionate sanction under the court’s inherent powers.

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/358/OBrien_v_gSaaGrr._Flick_S.D._Florida_January_10_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).