Probably illegal, but a GPS tracking and remote braking could be a “fun” (actually really dangerous) combo for a stolen bike. Of course it is just as likely that some unfortunate person would have unknowingly bought your stolen bike, so that’d be bad.
It’s probably legal. Modern cars do this, with the caveat that the owner can’t control the remote disabler.
Interesting legal gymnastics would required to make it legal for a Detroit automaker to do this, but not an individual. However, such gymnastics are sadly common these days and wouldn’t surprise me.
Another fun way is to gradually lock up the front wheel of the bike so it gets harder and harder to balance on it. If gradually enough this may be enough to convince thief it's just broken or bad.
Rented ebikes do this - take them outside their allowed geozone and they will periodically change the motor speed to throw you off (or at least go very slowly)
I think by “throw you off” you mean, sort of make the rider uncomfortable by presenting a slightly unfamiliar riding characteristic, right? Stopping the front wheel quickly enough could throw the rider off in a much more literal sense!
