I have had this happen 4 times with diff equipment, I have either set on the ground in a remote location well away from others or even set down and logged off and logged back in 5 or 10 mins later and its gone, I recently found a medium tent and setup and filled with stuff and logged off for a short bit, I understand there are other players but I was in a remote location on a low pop server and upon relogging in the tent was gone. I figured something like this would be a permanent setup and would not despawn or am I wrong.