Maybe it would be possible to make the automated car hard to convert to remote control. For example, there could be a central "smart box" which controls the vehicle, and it could communicate with satellite boxes that power and steer the wheels. The boxes could be tamper-resistant so it was hard to break into a box and take over the control system. And the communications lines between control and satellite boxes could be encrypted with a key that was locked inside the tamper-resistant portion, so that you couldn't hack in and take control of these lines.