It’ll be in the thief’s secure facility or a back alley where nobody can see him ripping apart pieces of the car to bypass the system or just ripping the parts off for resale.
It’s like those anti-rape devices that require cooperation to remove. Somewhat okay if you’re in public and attention will stop the rape. Useless if the rapist has no fear of attention.
Once the car is where he wants it to be, restarting it won’t be a concern.
Why not? Unless the thief can generate the unlock signal, he can't easily restart the car. It would be trivial to make the lock signal so complex that it couldn't be brute-forced, so I presume that has been done. The car could probably be hot-wired, but if the car is to be sold whole, it has to look and function as though it was whole. I suspect that would require replacing the ignition system. Replacing all the functionality of such a high-tech system sounds a lot more complicated than replacing a lock cylinder or re-keying a few old fashioned non-encrypted locks.
Obviously, I don't know much about car theft. Maybe this stuff is simple.