Some of this fascinates me to no end. You're under tyrannical regulations that not only require you to get enough sleep (imagine that) but also tell you WHEN that sleep must occur.
So, do you try to get the regulations relaxed to at least a tolerable level--- or do you write your legislative representative to DEMAND that everybody has to follow the same ridiculous regulations you do? I've seen way too much demanding of oppressive regulation for everybody for my liking, so much so that I daresay you won't be happy until they build enough prison cells to house every man, woman and child in North America. Then the guards can tell us all when to eat, when to sleep, what hours if any we can use the exercise yard and so on.
OK. I can't be sure, but I have a suspicion that some of this came about because certain truckers and trucking companies wouldn't police themselves, drove way too many hours with way too much weight and so on and so on, and made the government finally crack down on the industry for everybody's safety. If such a thing happens to vans, it may be because of the same reasons. Like it or not, your human body needs a certain amount of rest and sooner or later you will get it-- the only question being whether you stop at a rest-stop voluntarily or stop in a hospital. Or morgue, if your luck runs out.
Your van can only carry so much weight, beyond that you take serious risks. The door sticker gives the maximum safe weight, assuming of course that your vehicle is in good condition to begin with. Engineers being what they are, there's a safety margin in case you do go slightly overweight but that margin isn't as generous that it will allow you to run your springs to the bottom and start flattening your tires. The margin of error runs out somewhat short of that. Remember that your engine and tranny have to get all that weight moving, your suspension has to support it and your brakes have to stop it--- so, that door sticker is a wee bit more important than just a safety suggestion.
Think about it-- if we don't regulate ourselves, the government may have to-- and bureaucrats just love to over-regulate and make you press hard because there's seven copies and duplicate that----.