Anytime we roll into a CG and it is obvious that sites are available(and ours not reserved) we only pay for one night. We have until checkout the next day to pay for the next, and so on. By paying up front for 3, 4 or more nights and you leave yourself open to the the kind of nonsense described by the OP.
This strategy has served us well over the years. We have only needed to bail out early once up at Blue Water Lake south of I-40 east of Gallup. The first couple of days were ideal and then.... "they" arrived. Screaming kids, about 5, barking dogs, several, loud obnoxious drunks partying into the wee hours. We just laughed and hooked up our trailer and rolled out "very" early the next morning.... making sure to generate just enough noise to wake them. Guess they were just not "morning" people. :B
