Flames aside, this is a good point to keep in mind:
#1: My insurance company knows the make, model, year, and configuration of the vehicle I drive.
#2: My insurance company knows the exact GVWR, dry weight, and other specs of my RV.
#3: My insurance company knows my weight.
Putting two and two together, if there is a wreck, my insurance company wouldn't even have to bother with scales in order to find if my rig is overweight or not. They just look up vehicle weights on two charts, add my weight, perhaps add some for other items... and have a pretty accurate figure about loading or overloading.
Of course, things like airbags, 19.5" wheels, and other items help... but the weight rating numbers are not going to change, so even though a vehicle could handle 5000 pounds with modifications, if it says 2500 pounds on the sticker, that is what insurance will go by.