I didn't read your whole post, but I'm pretty sure they do not go to trial over a moving violation that does not involve any injury. It would be pretty silly to even try, he's not in any danger of losing his license or facing civil damages of any sort.

Also, saying you did not know the cop was there would probably go over poorly. How did you see a deer in the woods but not see a cop car parked near a stop sign? I get your point, but probably would go a different route.