I guess I'm jumping in late. My answer is this. If a tree or limb in a private campground has "scars" on it from being struck multiple times. The campground should remove it as part of general maintenance. Not removing it could amount to negligence on the campgrounds part when the next person hits it and damages their unit. Seriously the campground exists to allow campers a place to park and to park there they need to get there. Every time I call to reserve a campsite I am asked the length of my unit and how many slides, never the height. If they never ask the height I can assume they can accomodate every common unit out there. That said I would suggest always asking management to do any trimming that needs done. This is said in hindsight as I did trim a tree this year. The sight was billed as a "pull through" sight. It had a more than 90 degree right turn to get into it with not enough room on the left to swing far enought out to line up with the sight. The terrain sloped from left to right so the owners installed a 10"x10" on the lower edge of the site and filled behind it with stones to make a level site. Well till I made the turn my trailer wheels were going to climb right up over the corner of that beam. I can deal with that. Got out my levelers and built a ramp. As I am pulling up over that I notice a limb that I have to take the truck under to get the camper up in the site. This limb had the bark scraped off it from many previous encounters. I don't carry a saw. Another nearby camper did. I removed that limb and proceeded to park my camper in the site. I should have went to the management and had them remove the limb as they would have had the proper equipment and I would not have sweated near as much. Once that limb was removed you could look down that side of the site and all the trees/limbs were in a straight line. My reasoning at the time was "That limb should have been removed long ago with as many times as it had been hit." Still didn't make it right for me to do it without asking.