LCB's have done nothing in the past (as far as I know) and bedrolls have been used up to A16 when sleepervolumes came and pretty much ignored bedrolls.
Since A16 We have not used POI's to build bases in due to this, But for some reason (and I can't for the live of me remember from where) I think I read a devpost or something saying that LCB's should do that task now. (heck I could've dreamt it for as far as I know)
But. I done some testing in A21 with LCB's
After clearing out a Vanity tower I put down a LCB in the middle of it at (level 5 i think?), covering it all in the bounding box, (except the lower floors)
We left that town for a couple of weeks and returned to the tower. Loot had respawned, but no zombies had respawned inside (Except one soldier which might be a bug ?)
This is why I'm so curious about the status of LCB's. On other POI-bases we tried building there's both a LCB and several bedrolls, but still occasionally a zombie spawns inside the area.