In Australia to activate a sim you need a form of ID, if you were to put a sim card in a GPS tracker you could easily be identified. air tags not so much.
Still, even if not linked through purchase, the device will communicate back to a number controlled by you, fairly directly. A lot of obvious and hard-to-mask effort to emulate something that's provided as a COTS package with far harder tracking back to you.
TL;DR: this was possible previously, for fairly determined and advanced users; now it's available to anyone on a whim.