Maybe because in BC the Motor Vehicle Act definition of a commercial vehicle includes, "a motor vehicle having permanently attached to it a truck or delivery body," I'm in BC and every personal use pick up I've owned had "commercial" for the vehicle type listed on the vehicle registration.
Not to say a pick up is entirely governed by the BC Commercial Transport Act. But I wouldn't want to be over Licensed or axle weights (to circle back to Tundra).
In BC I have seen road side checks set up - pretty sure by CVSE (Commercial DOT Enforcement) - pulling over RVs and travel trailers. At least once I saw a portable scale being used. And then there are always the seasonal, mandatory watercraft inspection stations, usually at weigh scales. Don't know if those personnel are affiliated to CVSE but that location might be too close for comfort...
Of course that's in BC, and I don't expect outsiders to care much.
Agreed. Thing is, many threads on, "I'd be overweight, can the truck take it" wrap up with a reassuring indemnity declared for legal and insurance coverage concerns - if you have an accident while overloaded. Seemingly, that's the end of any concern.
BC is an absolute MESS, and most cops outside of CVSEs are confused themselves.
If they wanted, CVSE can enforce both GVWR (only applies to light trucks), AND registered GVW (think GCWR). But if you have an RV, boat, horse, or "car trailer", it does not count towards registered GVW. I can have a Ram 1500, tow a 20,000 lbs boat trailer, and perfectly legal in CVSE's view, as long as I dangerously load the boat so it only has 5% tongue weight. So much for "safety" huh?
But, if you have a tandem flat deck, load up a few ATVs, now the trailer is "commercial", and do count towards GVW. A stock F350 dually towing that would be illegal, unless you know to upgrade your GVW at time of registration.
And yes, they could roadside weigh you to further enforce GVWR, on top of registered GVW. But usually something has to trigger that - visibly overloaded.
Here's the kicker - RVs do not have GVWs. So if you put a sleeper on an F550 chassis cab, or even a retired Peterbilt, register it as a "motorhome". Now you can legally tow a flatbed with Cat D6 dozer. CVSE may be all over you, but nothing they can do as your GVW would be blank on the registration. So long as it's strictly for pleasure, and not for hire. Messed up rules we have!