As a camp host at a very popular NFS campground within 50 miles of four small cities, I've had to shush campers a few times. I usually wait until 15-30 minutes after quiet hours start on the theory that 10 pm is a wee bit early and most folks quiet down on their own fairly soon anyway. But that isn't always so. If they don't shush I have only one recourse: call the law. If I do that, somebody's going to jail, and after I explain that to the offender, they've always gotten quiet for me (knock on wood). I do recognize that as camp host, I have a bit more authority than the average camper. We do attract a few party animals from time to time, but perhaps because our sites lack hookups and even electricity, we seem to get fewer of them than campgrounds with all the amenities.