It would be hard to produce proof that an accident didn't happen. I would suggest the cameras, but then I would have to support the state of surveillance we already have. In theory, the guy I didn't kill might be grateful and want to cooperate to help me in thanks, but then of course you open the window for exploitation that you mention. It relies on a very high trust society. It just burns me that they are so quick to jump on your mistakes, but you get no credit for your good efforts. A guy who does 30,000km/year and has an accident every year will be judged more dangerous than someone who does 5,000km/year and has an accident every 2. The first guy is a better driver and avoids more accidents through good situational awareness, but runs into the problem of the statistical inevitability of accidents/km driven.