I recently bought an ebike that doesn't include GPS tracking. I was thinking of hiding an Apple AirTag under the seat, but then I read this:

"AirTag is designed to discourage unwanted tracking. If someone else’s AirTag finds its way into your stuff, your iPhone will notice it’s traveling with you and send you an alert. After a while, if you still haven’t found it, the AirTag will start playing a sound to let you know it’s there.

Of course, if you happen to be with a friend who has an AirTag, or on a train with a whole bunch of people with AirTag, don’t worry. These alerts are triggered only when an AirTag is separated from its owner."

(https://www.apple.com/airtag/)

So in an effort to prevent stalkers from tagging victims, the AirTag beeps to give away the fact that it's tracking something "separated from its owner." This makes it useless for my use case because if my bike is stolen, it will be "separated from its owner."