In BC I even asked about this in my 5er days about the trailer weight for the extra driving licence deal, and they said they use the axle weight scales if it came to checking for that. They don't even do all the rigamarole to get the truck weight and then derive the pin weight to add to the axle weight for the true total weight of the trailer. So in real life, it seems you get an extra weight (pin weight) they don't count, never mind what the rule is based on trailer total weight.
Of course that has no meaning for a truck camper situation, where they go by appearance to pull you over, if ever.