The Supreme Court limited location tracking. Does it reach plate-reader cameras?

Kagan's majority: a slice of a database is still a search

In Chatrie v. United States, Justice Kagan wrote for the majority, with Barrett dissenting, that individuals hold a reasonable expectation of privacy in their cell-phone location data. Pulling a narrow slice from a massive database, the Court held, does not dodge that protection.

The Yahoo piece aims that logic at Flock Safety's automated plate readers. Its test case is a suit filed in October 2024 by Lee Schmidt and Crystal Arrington against the city of Norfolk. On appeal at the Fourth Circuit, the plaintiffs have the ACLU, EFF, and Cato Institute behind them. The article's thesis: Chatrie knocks the legs out from under the "short retention means no search" defense.

Where the analogy strains

The standout reply gave the article credit, then dismantled its optimism:

To its credit, the article covers all the reasons why the Chatrie decision won't be determinative for this case. But the headline and narrative paint a way too optimistic (if you're anti-Flock) picture of Chatrie's impact. In particular the search identified by Chatrie (Google's database of expected-private location records, including movement in the home and other private spaces) has almost no analog in third-party-owned recordings of public movement.

— a reader who worked through the ruling's limits

Another reached for an analog world where the surveillance is human:

Let's say a local police department hired 175 police officers, each being told 'Go stand on this particular intersection with a pad of paper and write down every license plate you see'. This would be a stupid use of resources, but is not outside the realm of something a well-funded police department could do.

— a commenter with a pen-and-paper thought experiment

A third traced the doctrine back to its origin:

The fourth amendment does not say 'private conversations,' so when police started tapping phones, the courts focused on whether the phone tap physically intruded on somebody's house, papers, or effects.

— a commenter tracing Fourth Amendment doctrine from Katz

Chatrie widened privacy doctrine around a private phone log. Whether it reaches cameras pointed at open public roads is a different question, and that analogy is where this case will live or die.