We just had this happen yesterday. We arrived to a nearly empty campground and was told we would have to pay $3 per hour for early checkin on top of the $48 a night. We paid it because we have business here and wanted to get going. When it doesn't require any more effort on the part of the staff, I don't understand it. If they had to hustle to "clean" a site that would be different. Incidentally, when we called earlier in the morning to ask about availability, we were told they had plenty of sites and to just come on it. . . nothing about an early checkin fee.
Dale