I really can't believe the responses to this that say the poster has the issue.
Bottom line, you have a class b RV, so you can't just leave part of it there to hold the site. Packing up everything to go hiking shouldn't be required because others are less than ethical. We have had blocks grabbed, and an entry mat, plus site poaching until the camp hosts booted them, while we were out hiking and long before checkout time. The post tag clearly indicated were there for that night each time.
If you think it is OK, then you would probably also be the first one to "assume" that the site was vacant, long before the next check in time, and claim your booty.
If we find something on a site when we check in, we turn it in to the campground office, as they usually know who as there and could contact them if it is valuable. Or maybe the people will come back for it. Keeping it as found treasure is just not right, IMO.
We know people who put a big orange "occupied" cone on their site when gone, with their name on it, (as do we), and they had one of them stolen.
This is not the posters problem, but it is pretty to see how easy it is for folks to justify it to themselves.