LED Message Board For Cars Lets You Communicate With Drivers Behind You

OK, this sounds amazing, but really dangerous. Imagine if you could say anything you want to the car behind you with a message written on the back windshield of your car. This company designed a system hooked up to your cellphone that allows you write messages on your phone and they are displayed on your car windows and back windshield. The idea behind it, according to creators, is to prevent road rage incidents. People will be able to apologize if they made a mistake. But let's be honest, 99.9% of times it will be used to insult somebody. What do you think, is this an awesome or horrible invention?