The importance of knowing how tall your rig really is

I watched a DP rip two large branchs off a tree while backing into his site. His DW never telling him to stop. Nice tear in his roof and all he could say was I guess I'll have to get that fixed next week. At our first stop we spent 15 minutes trimming trees so we could fit into our spot and the ranger came by and apologized for not having the trees trimmed up. Will start carrying a pole saw to make this easier. Travel on.