Privacy advocates got access to Locate X, a phone tracking tool which multiple U.S. agencies have bought access to, and showed me and other journalists exactly what it was capable of. Tracking a phone from one state to another to an abortion clinic. Multiple places of worship. A school. Following a likely juror to a residence. And all of this tracking is possible without a warrant, and instead just a few clicks of a mouse.
How is this not a warrantless search?
It is, but the USA hasn’t cared since Snowden.
Because a carrier’s data on you is not your person or belongings. The companies holding this data are selling access to it, so it’s not being searched, it’s being offered.
In other words, the same reason as why they don’t need a search warrant if there’s a breaking and the business across the street volunteers their security camera footage, even if you’re on that footage.