If their focus is to say stop a teen driver for taking the car when they shouldn’t , I would A: take the keys so they can’t get in the car . B: if they do take it correct the behavior however your parenting model seems fit .
IF you were to install a device that shuts off the car after it is taken the last thing I would want is for my kid who took the car to be driving and not be able to steer or stop the vehicle because I cut power and cause harm potentially
Just my 1 cent thought