I'm retired and do my best to camp on weekdays. If some asshat puts out a couple chairs and/or a pup tent on Wednesday, hoping to save the camp spot until Friday evening when they show up for the weekend, AND I know it, they won't find the chairs or pup tent unless they look in the dumpster. I'll have enjoyed my camp spot and be cleared out by the time they arrive.
The rule is; you must occupy the camp spot on the first night, or it's available. I don't care if it's paid for or not, if it's not used, it's not saved. Just means you lost your money. It's not like you're there to do anything about it. If someone did approach me and claim they left their mark on the spot, I'll only claim that there wasn't any chair or pup tent but I think I did see one or the other in the dumpster.
Life is too short to let someone hog up a spot they aren't using that night just because they paid for it. Just doesn't work that way...