Some do have the rule, so I have heard.
I have never encountered one.
When and if I do, one of the benefits to being on wheels is that I can go on down the road.
They question the age of my rig? On down the road!
They only allow one pet in an RV? On down the road!
They have any other rules I don't like? (no firearms, no beer, whatever) On down the road!
(actually, I seldom have firearms unless going to the mountains, but I almost always have beer. I just object to them trying to tell me what I can carry in my traveling home!)