There was a security researcher in NYC that wrote about recovering his stolen scooter with an Airtag that discussed part of this question. At least some of the shops know they've got stolen merch and actively look for Airtags or other trackers.
I have an airtag on mine but I’m not super convinced it will make a difference:
- whenever I pick up the bike to ride it after a long period of not using it (say overnight or after a day of work), the airtag starts ringing. I don’t know why it does that but it would for sure tip the thief off
- don’t iPhones and maybe androids now show some kind of notification and offer to disable the tag if a tag you don’t own starts following you? That would also prevent me from finding the bike
- AirTags don’t report their altitude, only their location. Good luck figuring out in which apartment and on which floor it’s kept. Police would most likely decline to help as they can’t search every apartment
I've always figured that if I buy a bike from Craigslist, I should check the serial number and look it up on bikeindex.org. If I ran a used bike shop, that would definitely be part of my procedure.
Found it:
https://www.cnet.com/culture/guy-successfully-hunts-down-his...