The 'weight police' that I've talked to over the years are looking for trucks that are over weight.
They don't care about RVs. Since the general problem caused by an overweight RV is blowouts they see it as a self-correcting 'problem'. The same with broken axles, broken frames, etc.
As mentioned above - only in a fatal accident might the police, or coroner, investigator look at possible weight as a contributor. More than likely rather than try to prove the RV was overweight, they would just cite the driver with failure to maintain control of his rig.
Another point - I don't know if a vehicle can be cited for being over any of the sticker weights. I've seen a lot of vehicles which are obviously over the sticker weights - and never seen a police officer care. There are laws about certain vehicle weights - but they are all total gross weight.
I wouldn't say authorities never weigh a RV, but it is few and far between.
