According to this article https://petapixel.com/2021/04/26/apple-airtags-anti-stalker-feature-explained-how-it-can-track-thieves/ an AirTag will only alert a bike thief that they’re being tracked when the thief returns to their home, apparently determined from their address book. This does seem to mean that in the event of a theft you could (in an ideal world) go straight to the police and get them to track the thief down in that initial post-theft window.
According to this article https://petapixel.com/2021/04/26/apple-airtags-anti-stalker-feature-explained-how-it-can-track-thieves/ an AirTag will only alert a bike thief that they’re being tracked when the thief returns to their home, apparently determined from their address book. This does seem to mean that in the event of a theft you could (in an ideal world) go straight to the police and get them to track the thief down in that initial post-theft window.