A federal judge says a license-plate camera network is unconstitutional mass surveillance

A federal judge in Tulsa has done something rare: she named the constitutional mechanism that turns a license-plate-reader network from a useful police tool into "indiscriminate mass surveillance."

Judge Sara Hill ruled this week that a Tulsa County sheriff's deputy violated the Fourth Amendment when he searched a woman's Flock Safety license-plate-reader history without a warrant. The search turned up 91 pounds of methamphetamine in the woman's car, but Hill ordered all the evidence suppressed as the fruit of a poisonous tree. The case has been reported by 404 Media and TechCrunch.

Flock Safety is a network of automated license-plate readers, the small pole-mounted cameras that log every passing vehicle's plate, make, model, and time-stamped location. The cameras upload those logs to a shared database that law enforcement agencies can query on demand. The same infrastructure that lets a deputy pull up a stolen car's path through three counties also lets an officer track a former partner's commute.

In the Tulsa case, the deputy had no apparent reason to query the woman's plate other than that her car carried a California plate, according to Hill's opinion as summarized by TechCrunch. The travel history the query returned then became part of the deputy's justification for searching the vehicle. That sequence is what makes the case matter beyond the meth bust.

Hill's opinion leans on the 2018 Supreme Court decision in Carpenter v. United States, as legal commentary at Law Commentary lays out, which held that accessing seven days of cell-site location information requires a warrant. Carpenter turned on a recognition that long-term location tracking is qualitatively different from following someone on a single occasion. Hill extends that logic to a passive, networked camera system that catalogs every vehicle that passes any Flock camera, all the time, and makes the records available to law enforcement on demand.

"Tracking people's location becomes constitutionally problematic when law enforcement can indiscriminately and passively catalog your whereabouts over an extended period of time and then use that information for any purpose whenever convenient," Hill wrote, as quoted by TechCrunch. That is the part of the ruling that travels.

The opinion is not a ban. It binds only the parties in the case and is not binding precedent in any other federal district. As Mashable notes, the legal effect is closer to persuasion than to circuit-wide law. But a federal judge using the phrase "indiscriminate mass surveillance" to describe a deployed commercial surveillance system is the kind of language that gets quoted in motions to suppress, in state legislative hearings, and in procurement offices deciding whether to renew a Flock contract.

Florida and Texas have both said in recent months that they will stop using Flock, a bipartisan cancellation pattern that suggests the ruling lands on a procurement landscape that is already shifting. On Friday, Sen. Bernie Sanders (I-Vt.) introduced the Block Flock Act, which would bar federal agencies from using automated license plate readers such as Flock, per TechCrunch's report.

CEO Garretty Langley, who has publicly called for a compromise between privacy and public safety and apologized to women stalked by officers using the Flock system, is scheduled to take questions about the ruling on stage at TechCrunch Disrupt this week. The company has also offered voluntary employee buyouts as a way to shrink its workforce amid contract cancellations, according to CBS 12's coverage.

The next concrete milestone is the appeal. The Tulsa County Sheriff's Office and the Oklahoma Attorney General's office have not said whether they will appeal the suppression order, but if they do, the Tenth Circuit will be the first federal appellate court asked whether Hill's reading of Carpenter applies to networked ALPRs. Whatever the appellate panel decides will set the binding rule across the six states in the circuit. The full district court opinion is expected to be published in the coming days.

Hill did not invent a new right. She wrote down, in a published federal opinion, the constitutional math that turns a cheap, ambient, always-on camera network into a search. State and federal offices now have a working template for arguing that same math in their own cases.