Patterson v. Digital Federal Credit Union
California Court of Appeal, Fourth Appellate District, Division Two · Cal. Ct. App. · California bar guidance
Conduct
Self-represented appellant's brief cited at least eleven nonexistent cases, misused real ones, and attributed a quotation to a case that does not contain it.
Consequence
No sanction: arguments resting on fabricated authority treated as forfeited, judgment affirmed, and remand to consider a vexatious-litigant designation.
Lesson
Here the court did not sanction; it treated arguments built on nonexistent authority as forfeited and decided the appeal without them.
Verified September 29, 2026
- Citation
- Patterson v. Digital Federal Credit Union, No. E085332 (Cal. Ct. App. 4th Dist. Div. 2 June 23, 2026) (nonpub. opn.)
- Decided
- June 23, 2026
Summary
Self-represented appellant Trina R. Patterson appealed a Riverside County judgment dismissing her "petition for entry of default administrative judgment, satisfaction of lien, damages, and injunctive relief" against Digital Federal Credit Union after she declined to amend following a demurrer. The petition claimed that past-due notices she had marked "Accepted" and returned, and the credit union's silence, had discharged her auto loan, personal loan, and credit card balances and entitled her to $128,625. The court found that her opening brief "contains citations to cases that do not exist, citations to cases that do not stand for the propositions for which they are cited, and quotations that do not appear in the authorities cited." Among "numerous cases that do not exist" it named eleven, including Hagood v. Sony Corp. of America (7th Cir. 1988) 846 F.2d 1145 and Rappaport v. Gelfand (1961) 197 Cal.App.2d 611, and gave two examples of misused real authority: People v. Superior Court (Romero), a criminal case cited for a Uniform Commercial Code proposition, and a quotation attributed to Strong v. County of Santa Cruz that "Strong does not contain." In a footnote it said the errors "bear the hallmarks of fabricated legal authority created by generative artificial intelligence (AI), commonly referred to as AI hallucinations."
- AI tool:
- Unidentified (the court states the citation errors "bear the hallmarks of fabricated legal authority created by generative artificial intelligence (AI)"; no finding or admission of AI use, no tool named)
- Amount or terms:
- None: arguments resting on nonexistent cases and quotations deemed forfeited; judgment affirmed with costs to respondent; trial court directed to hold a noticed hearing on whether to declare the appellant a vexatious litigant
How did the court address the AI-related conduct?
In an unpublished opinion by Justice Menetrez (Acting Presiding Justice Miller and Justice Lee concurring), the court affirmed the judgment and awarded Digital Federal its costs on appeal. It held that "[n]onexistent cases and nonexistent quotations do not support the propositions and arguments for which they are cited," so "we consider those arguments forfeited too." The footnote added that pro se litigants, like attorneys, "must check and verify every citation," and noted that attorneys who filed AI-hallucinated citations have been sanctioned, that a pro se litigant has been warned of the same possible outcome, and that extensive reliance on nonexistent authority "may justify striking a party's briefs or dismissing the appeal." The court imposed no sanction on Patterson and did not issue an order to show cause. Citing "the frivolous nature of Patterson's litigation in this case" and her statement at oral argument that she had been involved in litigation for 16 years, it directed the trial court on remand to hold a noticed hearing on whether to declare her a vexatious litigant and enter a prefiling order, expressing no opinion on the result.
Why does Patterson v. Digital Federal Credit Union matter for law firms using AI?
The opinion in this appeal is the quieter half of a pair. The same court and authoring justice decided Patterson v. Nuvision Credit Union nine days later, on a very similar brief, and there issued an order to show cause and imposed a $500 sanction. Here the court did neither. It catalogued the fabricated authority, stated in a footnote that the errors “bear the hallmarks of fabricated legal authority created by generative artificial intelligence (AI),” and then applied an ordinary appellate consequence: arguments that rest on nonexistent cases and quotations are forfeited.
The Nuvision opinion explains the sequence. According to that opinion, the court’s March 19, 2026 tentative opinion in this appeal had already flagged the nonexistent cases and quotations, and Patterson told the court at the later show-cause hearing in Nuvision that she took no corrective action in this appeal because no order to show cause had issued here. The Nuvision panel treated that inaction as a reason to doubt her claim that she had learned her lesson.
The remand direction is the other notable feature. Rather than sanction Patterson on appeal, the court directed the trial court to consider whether she is a vexatious litigant under Code of Civil Procedure section 391 and whether to enter a prefiling order, pointing to her statement that she had been litigating for 16 years. Firms documenting compliance may wish to consider that, in this court, fabricated authority from a self-represented party produced forfeiture in one appeal (where the court separately directed a vexatious-litigant hearing based on her frivolous litigation and 16-year history) and a monetary sanction in the companion appeal, where the court had issued an order to show cause.
Implications for your firm
Operational steps a firm reading this case may wish to consider documenting. Strategic and rule-application calls belong to your firm's attorneys.
- Verify every citation in a brief, including quotations; this court treated arguments supported only by nonexistent cases or quotations as forfeited.
- Review a self-represented opponent's brief for nonexistent authority; the court named eleven nonexistent cases in this brief.
- Consider that an appellate court may address frivolous pro se litigation through a vexatious-litigant referral to the trial court rather than an appellate sanction, as this court did.
Sources
Primary sources
- AI attribution: the opinion says only that the errors 'bear the hallmarks' of AI-generated authority; it makes no finding that Patterson used AI. The attribution beyond that statement is a Charlotin tracker inference ('Implied').