Where I usually go camping, there are sites marked as "RV accessible" but everybody is welcome to camp there.
The spots are pretty small as this is campground in the mountains, with lot of slopes and tight turns between the trees. The developers put huge boulders to prevent cars driving between the trees and it is very funny to observe 4 cars squeezed on the pad design for 2.
Being self-employed we go there mid week. One time we decided to stay Friday night and that was sleepless night if you know what I mean.