Another claim being made on the forums is that some people have been refused their insurance claims because their vans were overweight. There are 2 aspects to this claim that need to be examined but, in a nutshell, these stories are in all likelihood false or a misinterpretation of the truth.
Firstly, like other myths on this site concerning weights of vehicles and trailers, if you have set up your rig properly and confirmed it is within manufacturer’s specifications, then you have nothing to fear in the event you need to make a claim on your insurance. That said, I find it very difficult to believe that an insurance company could prove beyond a reasonable doubt, that a rig was overloaded unless they were able to gather all the pieces of a wrecked vehicle and weigh them to determine the exact weight of the vehicle before the incident. It’s just not possible nor would it be feasible.
The other issue is that the ATM of your trailer may be higher than the tow capacity of your tow vehicle. There is nothing wrong with doing this and thus should not void your insurance. ATM or Aggregate Trailer Mass, is a rating, not an actual weight. It cannot be assumed that just because a trailer has an ATM of say 3500kgs that it actually weighed that at the time of the incident. It may have been empty and only weighed a fraction of that amount.
If you want to be sure, I would advise people to contact their insurance companies and get an explanation from them, preferably in writing.