What was hallucinated

Misrepresented: Case Law | McDonald cited In re Estate of McCreath to claim the trustee’s duty of impartiality cannot be overridden by trust terms; the court noted the case does not address that duty and does not support the proposition. || Misrepresented: Case Law | McDonald relied on In re Green Valley Financial Holdings for the same duty-of-impartiality proposition; the court explained the case does not reference that duty and does not support his claim. || Misrepresented: Legal Norm | McDonald asserted C.R.P.P. 31(c) required filing JDF 942 for a trust accounting; the court held the rule imposes no such requirement and JDF 942 is for decedents’ estates. || Misrepresented: Legal Norm | The trustee invoked § 15-12-903 to authorize a surcharge against a trust distribution; the court held that statute applies to wills, not trusts.

Details

The court noted that:"both Lehr-Guthrie's and McDonald's briefs are replete with errors in their citations to case authority, such as repeated citation errors, references to nonexistent quotes, and incorrect statements about the cases (for instance, as noted above, the two cases McDonald cited for a proposition relating to the duty of impartiality don't even reference that duty). This suggests to us that the briefs may have been drafted with the use of generative artificial intelligence (GAI). “[U]sing a GAI tool to draft a legal document can pose serious risks if the user does not thoroughly review the tool's output.” Al-Hamim v. Star Hearthstone, LLC, 2024 COA 128, ¶ 32. Self-represented litigants must be particularly careful, as they “may not understand that a GAI tool may confidently respond to a query regarding a legal topic ‘even if the answer contains errors, hallucinations, falsehoods, or biases.’ ” Id. (citation omitted).4 We advise the parties that errors caused by GAI in future filings may result in sanctions. See id. at ¶ 41. "The court warned that future errors caused by AI could result in sanctions.

Sanction teardown · Colorado Court of Appeals, USA · 2025-07-03

Matter of Sewell Properties Trust

What happened

In Colorado Court of Appeals, 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:

Misrepresented (Case Law)

McDonald cited In re Estate of McCreath to claim the trustee’s duty of impartiality cannot be overridden by trust terms; the court noted the case does not address that duty and does not support the proposition.
Misrepresented (Case Law)

McDonald relied on In re Green Valley Financial Holdings for the same duty-of-impartiality proposition; the court explained the case does not reference that duty and does not support his claim.
Misrepresented (Legal Norm)

McDonald asserted C.R.P.P. 31(c) required filing JDF 942 for a trust accounting; the court held the rule imposes no such requirement and JDF 942 is for decedents’ estates.
Misrepresented (Legal Norm)

The trustee invoked § 15-12-903 to authorize a surcharge against a trust distribution; the court held that statute applies to wills, not trusts.

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

The court noted that:"both Lehr-Guthrie's and McDonald's briefs are replete with errors in their citations to case authority, such as repeated citation errors, references to nonexistent quotes, and incorrect statements about the cases (for instance, as noted above, the two cases McDonald cited for a proposition relating to the duty of impartiality don't even reference that duty). This suggests to us that the briefs may have been drafted with the use of generative artificial intelligence (GAI). “[U]sing a GAI tool to draft a legal document can pose serious risks if the user does not thoroughly review the tool's output.” Al-Hamim v. Star Hearthstone, LLC, 2024 COA 128, ¶ 32. Self-represented litigants must be particularly careful, as they “may not understand that a GAI tool may confidently respond to a query regarding a legal topic ‘even if the answer contains errors, hallucinations, falsehoods, or biases.’ ” Id. (citation omitted).4 We advise the parties that errors caused by GAI in future filings may result in sanctions. See id. at ¶ 41. "The court warned that future errors caused by AI could result in sanctions.

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/556/Lehr-Guthrie_v._Sewell_USA_3_July_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).