I think I figured out a cause of the digging, From what it looks like sounds travel straight through blocks and dirt so the Zombies hear when we are at bedrock or like when I was indoors in a Vanity Tower POI on the 4th or 5th floor wrenching, zombies down at the street level heard me and came looking.
If the mod could check for the shelter status and dampen sound emitted by a configureable value it could probably fix this, I absolutely love outdoors to see zombies hearing gunshots and honing in, but it does feel weird when indoors that small sounds still travel out so far.
And yes, LCB do indeed stop spawing, they changed that a couple of alphas ago (Or rather it's stopping sleepervolumezombies from re-spawning) But we get walkersim agents roaming straight past walls and spikes and turns to zombies inside our base when we come near which is what I'd like to prevent.
As far as I gathered from other posts regular world zombies can spawn only on terrain blocks (voxelblocks) which does seems to be the case when I have been testing, and also respects the 'canMobsSpawnOn' xml tag for the block.
Does walkersim respect that tag aswell when turning agents to spawned zombies? If it does then I can mod in zombiespawnproof terrain blocks to place inside the walls to actually have a point with the walls and spikes ^^
(how does it handle bedroll safezone for that situation?)