Im curious - did the OP tell anyone at the office that he was leaving (briefly to tour around) and that he would be back ??
Did the OP have property in the slot (camp chairs/table/grill etc) when he left ?
Im wondering if this campground might have some inconsistent policies, lazy employees or employees just trying to accommodate & please new arrivals....
They guided the OP to his slot (even when the campground was empty) and perhaps the new desk clerk didn't guide the new arrival (the same way the OP was) to their slot ....could they have told the new arrivals "just park in any open slot" ?