Rules don't apply to me, my dog is perfect

Every visit we make to any caravan site we see a dog owner demonstrate that there may be rules but they and their dog are exempt. Challenge any of these people (nicely) and a human version of a defensive/aggressive snarl ensues. 

Five minutes ago we saw compliance but not as we know it; two ladies with dog on lead, fine? No, not fine; dog had a lead on but the lead was trailing on the ground. Effectively the dog was free but the "dogs should be on leads" rule was being observed? Not in both the letter and spirit it wasn't.