Meh, you've had these for years. I'd put it at even money that some RF protocol stacks on recent vehicles are vulnerable to exploitation and connected to one of the CAN buses on the vehicle so you can pivot to a more critical system. Hurray for drive by exploits (literally).
I'm honestly surprised that criminal organizations haven't paid/coerced engineers working how to steal certain cars using a remote control, because I'm pretty certain that with some effort, it's possible.
Fingerprint the requestor by IP; what's that? You're making more than 1 request per second to more than more vehicle ID and you're not a trusted partner? BAN LIST