You cant have a remote cutoff option due to lawsuits. What if a zipcar got turned off on the highway and caused an accident, they would be sued
Doesn't that just not let you start the car? I don't think it turns off the car.
edit: according to [1], OnStar "can limit the speed at which it can be driven, remotely lock the ignition so that it can’t be started, and track the car’s location".
[1] https://www.bostonglobe.com/business/2014/09/07/how-tech-mak...
(as for the original question, even ignoring situations where you need to have acceleration to get out of them, just cut the power steering on someone who has never driven without it and see how well they pull over to the side of a busy intersection or the like)
Having had power steering (and power everything else) go out on me in an F250, it's pretty much kind of terrifying. Brakes? Sort of. Steering? Sure, if you put your back into it.
One of the isuue, and probably what the thief are gaming is how it takes to be reported.