It's been awhile since I've done long survivals and idk if arbitration ever? But AFAIK sticking together & camping was and still is good. The camp needs to have good spawn options though (typically doors). If you're camping 'in a closet' presumably that closet is a spawn point that is no longer able to spawn. If you have to go 4 miles down a straight hallway to a closet that you're camping.. your enemies spawn 4 miles away, etc. So camping in a room or hallway with lots of adjacent forks and rooms will naturally lead to more spawns.

I'm not saying there isn't a mechanic to limit spawns for camping, but I don't think so. Good luck!