It's best to leave it alone until you are parked. Also if you have a car behind you at fast speeds it could cause an accident.
I agree there are a lot of things to be worked out. If the car behind you could could communicate with your car there would be no danger. Where the real challenges lay in this technology is in law. Who do you sue if an accident is deemed caused by faulty software. What if the company that created the software no longer exists. Then send in the insurance companies for a feeding frenzy and the list goes on.