If a car can be used as a wmd, get ready to lose yours, a bit like your privacy.
Why do you think modern cars come as standard with some kind of remote control equipment enabled and hard to disable by most people? Why do you think there's this sudden push to driverless cars?
If your car can be disabled anytime the manufacturer/government wants and you can be locked in your car at the push of a button you can be easily 'detained for your own protection' every time you dare to think.