One thing that some campgrounds here in the east are doing is having the person who rented the campsite sign an acknowledgement stating they understand quiet hour rules and the pet policy & pet clean-up rules. The check in person reviews the rules and witnesses the signature. I have seen this done with all campers regardless of age, type of rig, number of people in the unit.
It makes the person that signed responsible for the group and all pets. No-way to deny understanding the rules after signing.
Not sure what happens if you violate the policies, I have never tested it, but it does stipulate ejection from the park and loss of any pre-paid camping fees.
The contract combined with a presence of roaming security personel at night must work as many of these parks are as quiet as a grave after 10:30 or so.