I've been pulled over for the same shit. I go to work real early, I meet one of the guys I car pull with at a 7-11 at like 3:45am. When I got pulled over he mentioned that was the reason he pulled me over but that was obviously just an excuse, other than telling me that was the reason he pulled me over he never even talked about it. Instead he asked for my info, my passengers info, where we were going, where did we work, what time we had to be to work, and what we did at our jobs. I think the whole license plate light thing is just a super easy reason to pull you over to see what else they can find.