If police dispatcher can have such car stopped, then some attacker can do the same thing (messing up the engine, disabling brakes or whatever). A dream for criminals or someone even worse. And now imagine this thing happening on a massive scale and simultaneously. The whole idea is really absurd to begin with. It's very close to DRM in the spirit - overreaching preemptive policing. And has the same result - weakened security.
Now, if they want to make it properly, the owner of the car has to be in control of such defense measures. Not some external entity like police! That would be a proper security approach. Same thing as with DRM. It's not a protection for the user. It's a defense against the user. Same thing here, it looks more like a measure against drivers, rather than something to protect them from car theft.