[future10se]

> The fact that they let law enforcement know when someone is stalking someone with an AirTag shows that the data is available to them.

Not technically correct. Apple devices (and Android phones with the appropriate app) detect if an unknown AirTag is moving with them and makes it home, possibly signalling a stalking attempt.

The heuristics for this happen locally; Apple isn't "aware" of this happening. That said, when you first set-up an AirTag, the serial is tied to your account. Therefore, when you physically find an unknown AirTag and report it to law enforcement, they can then subpoena (or get a warrant?) Apple for information on the AirTag owner's identity.

The serial itself, and any personal identifiers, are not used in the locating process, however.

This is well documented in the paper above, in articles, as well as in reverse engineering efforts.