I have paid a pet fee numerous times. I have them with me so it is just part of the deal.
We put our home site in a rental pool when we are away. We have never had any problems with pet owners. No messes left in the site.
Kids on the other hand have been a bit of a bear. I have had section of fencing torn down and turned into bike jumping ramps several times. Oil and grease from the dad dumping it onto the brick patio right from the grill. Garbage, I can't describe that. These people are on a no rent to list now. They had no pets.
What can I say.