I'd bet 90% of truck campers are over weight when fully loaded. Obviously if there was "reason" to suspect an over weight vehicle was responsible for the accident, I'm sure an insurance company would be looking into it. Personally I wouldn't go asking my insurance company if being over weight would void my coverage. Why give them reason to suspect? My camper's weight sticker puts it within the carrying capacity of my truck. Add people, gear, fuel, etc, and I'm over weight. Chances are a person investigating more than likely would look at the campers weight and the cargo capacity of the truck. Without then seeing a few truck motors inside or something else crazy like that, I doubt they would start weighing people and baggage. that said, anytime you break the law, you are putting yourself in jeopardy. So be prepared to take your punishment.