I think they all do these days (even my 1998 car has one), and they've already been used against drivers. Since they record things like speed, brake and accelerator application, etc., they've been used in prosecuting drivers in traffic accidents.
There were car rental companies that used GPS trackers to "fine" renters for driving too faast. They lost in court over doing that, but what would stop a government entity from doing the same thing. Of course, we will get people saying it's ok, just follow every rule and the government is your friend. Just like Soviet Russia. Yup.