Why bother with site rules?

I often see amongst other rules on sites that dog's must be kept on a lead! in fact in my experience it is rare to see this. Why do so many caravanners flout site rules and more to the point why don't site wardens enforce the rules thay make. If they are to yellow and scared to say something then why have the rule in the first place. I recently witnessed a dog wander over to another vacant pitch, squat and have a wee and about 20 minutes later a caravanner pulled onto the pitch and put up an awning right where the dog had a wee so the odour would have been inside his awning and if he put a ground sheet down it would have been right on top of the wee. A lot of caravanners seem to let their dog/dog's wander around without a care in the world what they are doing and where, rant over.