Mendones v. Cushman & Wakefield

What happened

Ariel and Maridol Mendones, representing themselves, sued Cushman & Wakefield and others in a housing dispute (Case No. 23CV028772). In opposing a defense motion for summary judgment, they filed exhibits that included 2 videos presented as testimony from a witness named Geri Haas, photographs said to come from a Ring doorbell camera, and screenshots of text messages.

On reviewing the filing, Judge Victoria Kolakowski suspected that 9 of the exhibits had been altered or created with generative AI (software that produces new images, video or audio on request) and issued an order to show cause why sanctions should not be imposed.

What the court did

In an order signed September 9, 2025, the court compared exhibits 6A and 6C with a separate, authentic video of Ms. Haas that was also in the record. It found the voice, cadence, pauses, gestures and facial expression in the 2 exhibits to be markedly different and wrote that "exhibits 6A and 6C are products of GenAI and do not capture the actual speech and image of Geri Haas." The order also described a figure that appeared inserted into the Ring photograph, alterations in the message screenshots, and anomalies in file metadata.

Ms. Mendones acknowledged that AI had been used on some of the video exhibits but attributed it to others. The court did not accept that account. It noted that the device she identified could not run the Apple Intelligence features she described.

The court considered lesser measures, including monetary and evidentiary sanctions and a referral to the district attorney, and found them insufficient. It struck the operative complaint and dismissed the action with prejudice, writing that "a terminating sanction is appropriate."

Where it stands

NBC News reported that the plaintiffs moved for reconsideration and that the court denied the motion on November 6, 2025. This record did not confirm whether an appeal followed. The court stated that other exhibits remained suspicious but that it did not have the resources for a full forensic review of each one.

The obligation it engaged

The parties here were litigants rather than retained professionals, so the Standard applies by analogy. The exhibits were offered as recordings of a real person's words. Material generated by a system entered the record on the system's authority, which is what Independent authority excludes. Nothing in them could be confirmed against an independent source, and the one independent source available, the authentic video, contradicted them.

For experts and counsel, the matter shows where checking begins. The court identified the problem by comparing the exhibits with authenticated material of the same witness and by reading the metadata. Those are the same steps a competent examiner would take without any AI detection system, which is the governing test in its plainest form.

Sources

• Superior Court of California, County of Alameda · September 9, 2025
  Order re Terminating Sanctions, Mendones v. Cushman and Wakefield, Inc.
• Reason (The Volokh Conspiracy) · September 25, 2025
  Court Throws Out Case After Finding Plaintiffs Submitted Deepfake Videos and Altered Images
• NBC News · November 2025
  AI-generated evidence showing up in court alarms judges
• eDiscovery Today · September 25, 2025
  Deepfake Videos and Images Lead to Terminating Sanctions

What could not be confirmed

The signed order was read from a copy hosted by a third party, not the court's own portal. Whether the plaintiffs appealed after reconsideration was denied was not confirmed.