I don't understand the bad rap that liveaboards get. There was a liveaboard next to my dad's boat and he'd always call us if anything seemed strange, he'd throw an extra line or fender on if my dad couldn't get to the boat for an impending storm. There were about a dozen liveaboards in the club and they were all great. They each looked out for their little neighborhood.
I think if a marina is worried about a particular problem, they should solve that specific problem. If you don't want clothes drying on a line, make a rule for that. If you don't want an industrial trash barrel in the cockpit, make a rule for that. A decent liveaboard should be a huge asset to a marina. Regulating all liveaboards good and bad seems like throwing the baby out with the bathwater.