After all is said and done, it still comes down to a simple fact. The large powerful breeds are capable of inflicting significant physical damage IF they do bite. And no RV park owner has the time or expertise to determine the personality of every dog that may enter their park. Yes, you are probably more likely to be bitten by a high strung little yapper than a large dog. But where the yapper may break the skin and cause some bleeding, that large dog can tear flesh and muscle. I am not opposed to large breeds by any means. My Golden weighs 88 lbs. But the large dogs do require special considerations by their owners and by those who own or operate facilities in which they may enter.