I have no idea how it's designed, but it should put a credential on your phone which it can check via Bluetooth. That credential would presumably have an expiration date and the app should only need to validate it once when the status changes.
It shouldn't be checking anything during a ride. If it needs to be turned on at the start of the ride, it should do all the checks and give a green light or a red light (or some other clear indicator) before they start riding.
That way, the only way it doesn't go off if someone wears it while ignoring the "system is not active for safety" warning.
Shouldn't be a subscription in the first place, but hey, this is just a weird hypothetical.