I would just be building and watch a zombie walk straight threw the watchtower wall and attack me some aren't able to but I'd say 6 out of 10 zombies can walk threw player built building and have all seen them do it on regular houses and places on the maps

I didnt do anything have watched zombies walk threw stuff when not after me and have watched them do it while after me

For zombies to no longer be able to walk threw buildings