I'm currently staying at a COE campground in CA (third time here this winter) and everytime I've seen people mainly in small class C or B's come in late and leave early. Obviously I don't know for sure if they have paid or not but it just makes me wonder. There is no host here just a park ranger that comes by usually around 9-10am and again in the afternoon 3 or so. Also the gate closes at 10 and reopens at 6.
I've also seen a woman and her kids who looked like they were living out of small U-Haul box truck come in after 9p and make use of the showers then leave.
I guess I'm curious about this because it's somewhat of a moral dilemma. It's something I've thought of trying, arriving late and leaving early at a campground without paying. I'm mean if I'm not taking advantage of any amenities just parking and sleeping and leaving.