Matthews v City of Tacoma
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Matthews v City of Tacoma is a Washington civil appeal concerning alleged property damage and the City’s response to neighboring development. On October 20, 2026, Division II affirmed summary judgment for the City. The unpublished opinion also identified unsupported or nonexistent authorities in Mark Matthews’s briefing and suspected generative-AI involvement. Its disposition rests on claim preclusion, the public-duty doctrine and evidentiary and procedural rules, rather than a separate AI-use penalty.[1]
Background
The opinion recounts an earlier suit against the developer, Pioneer Land Development, that ended in stipulated dismissal with prejudice. Matthews then sued the City in July 2023, alleging that it allowed property damage and trespass, failed to enforce applicable requirements, and discriminated against him when declining to issue a stop-work order. The City contested those claims and obtained summary judgment.[1]
October 20, 2026 decision
The Court of Appeals held that claim preclusion barred the claims for injunctive relief, waste and trespass, based on the earlier litigation and the relationship between the developer’s and City’s interests. It held that the public-duty doctrine barred the negligence claim and that the claimed exceptions were not established. It also upheld dismissal of the discrimination claim because Matthews had not supplied admissible evidence creating a genuine factual dispute on a necessary element.[1]
The court explained that it did not need to decide the cross-motion timing issue to affirm, but concluded that Matthews had not properly scheduled his cross-motion under CR 56(c). It rejected the due-process and jury-trial objections to the proper grant of summary judgment.[1]
Suspected AI citation errors
Footnote 11 on page 10 states that some cited cases and municipal ordinances did not support the asserted propositions and that some authorities did not exist, leading the court to suspect generative AI. Invoking RAP 10.3(a)(3), it declined to address arguments unsupported by adequate legal authority. The opinion again notes defective municipal-code citations on page 18 and a nonexistent case in the cross-motion discussion on page 22.[1]
The court did not establish admitted AI use, impose a separate monetary AI sanction or adopt a general AI-drafting prohibition. Its final paragraph designates the opinion unpublished and directs filing for public record under RCW 2.06.040.[1]