Can you imagine the havok when terrorists figure out they can program cars to hunt and kill pedestrians in crowded spaces? Currently the terrorist needs to drive the vehicle, which makes it a suicide mission. How much more deadly would it be if it was reduced to just the cost of the car and a low chance of getting caught? How can we defend against this?
just throw in a off the shelf servo to control the steering wheel and two more to run the brakes and gas. Throw in a off the shelf RC controller and you got yourself a giant RC car.
Probably faster than trying to hack a car when you got a perfectly good no authentication interface.