I have already told you that no one has the right to limit another citizen's movement against their will. This is legally kidnapping, so any sane person woyld oppose it's use. That said;

There is no reason to limit this "app", as it us not technically feasable. It can never work, that is why the Police do not use it. They use the microwave transmitter version, with Very limited results!

The worst you could do, with an offensive app; is it would be possible to shut down your opponent's cell phone. This has been shown in court to be assault, so it is illegal already. If, in the comic books, you could make this "app" function; it would also be considered assault.

Of the six vehicles at my house, None (even the on star equipped) of them could be affected by the Internet. Almost 100% of those so attacked, would not even notice, as no function would change.

Those hacking cars for fun, are currently most impressed by controlling wipers. He had a hard link into his own car, and had expended several weeks of coding; just to reach his own wipers!

Since interducting personal Communications is already illegal ( if you shut down a 911 call, etc.); shutting down their ability to leave, would also be illegal, in the same fashion.