Many times, I've seen tent campers set up camp when they first arrive, then about midnight, fold everything up and go home.
At one campground, we had extremely young neighbors in the site next door, who arrived around 7, crawled into the tent, and left about 10. We figured they had an 11:00 curfew.;)
We do a variation on this. My husband and I stay overnight, but our daughter and her family come out for the day. The first time, our two-and-a half year old twin grandkids had so much fun that they turned their bedroom into a campsite the next day. It's become an annual tradition. In time, we hope to recruit more overnight campers.