When I lived in a residential neighborhood, a neighbor on the street leading into mine had a large tree with a large diameter limb located at a low level. It put a "dimple" in the cover of my roof-mounted satellite dish, which is the tallest object on my roof. We did not detect it until our next outing when the dish could not lock on to the satellite since it did not have full freedom of movement under the cover. I fixed the problem simply by punching out the dimple in the plastic cover.
Most campgrounds that have large rigs using them will have their limbs trimmed if only because other units before you have already "pioneered" the path and hopefully forced them to do some trimming. You are right to be concerned, especially in campsites that don't handle many bigger rigs. Be aware of your clearances and watch your route going in.
As for my experience, I started driving down that street on the left side to avoid going under that tree. Eventually he had it trimmed, possibly because it claimed some other victim(s).