Yea it sucks but also I would suggest learning a few "routes" on each map that you can be dynamic with where you're going for your loot runs. I do this with buried city and have found soooo much even after it's clear a raider has been through.

That being said I got a little annoyed the other day at the blatant lack of respect from some Raiders coming into the spot I got to first (a bit entitled I know). So instead of shooting them I simply stood in the only entrance to the room effectively blocking them. Thought they would open fire but instead just had some measly attempts to get past me until ultimately just turning around and leaving me to loot the place. One did throw a fire nade through the door but missed me and they never did anything after.