Plumbers & Gasfitters Union Local No. 75 Health Fund v. Morris Plumbing, LLC
U.S. District Court, Eastern District of Wisconsin · E.D. Wis. · Wisconsin bar guidance
Conduct
Here the plaintiffs' reply brief cited a purported Seventh Circuit case the court's staff could not find; the reporter cite led to a differently named case from another year and circuit.
Consequence
No sanction; the court said it suspected AI and put plaintiffs' counsel on notice that any future nonexistent authority "will result in sanctions." Plaintiffs won the motion.
Lesson
Here the court flagged a nonexistent case in a footnote even though the filer won the motion and the citation did not affect the result.
Verified September 30, 2026
- Citation
- Plumbers & Gasfitters Union Local No. 75 Health Fund v. Morris Plumbing, LLC, No. 23-CV-616-JPS, Order (E.D. Wis. Apr. 18, 2024) (Stadtmueller, J.), ECF No. 33
- Decided
- April 18, 2024
Summary
Union benefit funds and their trustees sued Morris Plumbing, LLC under ERISA for unpaid contributions, interest and statutory penalties for February 2020 through December 2022. After settlement talks carried out by email between counsel, the plaintiffs moved to enforce a settlement they said was reached on January 8, 2024, and Morris Plumbing opposed, arguing it had never agreed to the limited release of claims the plaintiffs proposed. In footnote 2 of its order, the court noted that the plaintiffs' reply brief (ECF No. 32) cited "Caserage Tech Corp. v. Caserage Labs, Inc., 972 F.3d 799, 803 (7th Cir. 1992)" for the proposition that a party's silence after the other side states its understanding of a settlement term shows agreement. The court wrote that "none of the Court's staff were able to locate" the case; that "[t]he citation goes to a case of a different name, from a different year, and from a different circuit"; and that staff could not find the case name with that year on Google or in legal databases. The order does not name the attorney who signed the reply or record any explanation from the plaintiffs.
- AI tool:
- Unidentified (the court wrote that it "suspects" the citation was "an instance of provision of falsified case authority derived from artificial intelligence"; no tool is named and the order records no explanation from counsel)
What did the court warn about?
Judge J. P. Stadtmueller granted the plaintiffs' motion to enforce the settlement agreement, holding that counsel's email exchange, ending in acceptance on January 8, 2024, formed a binding agreement that included the limited release of claims through December 31, 2022, and that the defendant's later objection to that term did not undo it. The court denied the plaintiffs' motion to compel discovery as moot, directed the clerk to administratively close the case, and ordered the parties to file dismissal papers. The court said the defective citation "does not ultimately affect the Court's analysis or disposition." It imposed no sanction for it, and warned: "If this is, as the Court suspects, an instance of provision of falsified case authority derived from artificial intelligence, Plaintiffs' counsel is on notice that any future instance of the presentation of nonexistent case authority will result in sanctions." The docket shows no further proceedings on the citation; the parties filed a stipulation of dismissal on May 21, 2024.
Why does Plumbers & Gasfitters Union Local No. 75 Health Fund v. Morris Plumbing, LLC matter for law firms using AI?
The citation issue in this ERISA collection case was a footnote to a ruling the plaintiffs won. The court enforced a settlement formed through counsel’s emails, holding that the defendant’s counsel objectively assented to a release limited to claims through December 31, 2022, and that his later objection did not undo the agreement. In the middle of that analysis, footnote 2 addresses a case the plaintiffs cited in reply, “Caserage Tech Corp. v. Caserage Labs, Inc.,” which they described as holding that a settlement included a disputed term when one side stated its understanding and the other did not repudiate it.
The court described what its staff did before drawing any inference. The volume and page led to “a case of a different name, from a different year, and from a different circuit,” and staff could not locate the case name with the stated year “either on Google or in legal databases.” The court then said it suspected the citation was falsified authority “derived from artificial intelligence.” That is a suspicion, not a finding, and the order records no explanation from plaintiffs’ counsel.
The consequence was a notice, not a sanction: “Plaintiffs’ counsel is on notice that any future instance of the presentation of nonexistent case authority will result in sanctions.” The parties stipulated to dismissal about a month later, and the docket shows nothing further on the citation. Firms documenting compliance may wish to consider that here the court treated the citation as worth a written warning even though the supported proposition was unnecessary to the result and the filer prevailed.
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 reply brief, including those offered in support of a central argument. Here the court noted the defect even though it said the citation did not affect its analysis.
- Consider that a warning can issue to the prevailing party. Here the plaintiffs obtained enforcement of their settlement in the same order that put their counsel on notice.
- Document how a cited case was located. Here court staff searched the case name and year on Google and in legal databases before concluding it could not be found.
Sources
Primary sources
- AI attribution: the court's statement is a suspicion ("as the Court suspects"), not a finding; the order records no admission or explanation from plaintiffs' counsel and names no tool.