Board Thread:Suggestions forum/@comment-27668672-20170519151014/@comment-25565811-20170520072323

''TheCrafter4000 wrote: ... so no orc can ever enter my land. ...''

That's not true, Orcs can wander in from the outside. The same would be the case with friendly NPCs in your buildings with the advanced banner option: They wouldn't spawn there, but would be able to open doors and wander in. But your option would reduce the amount of NPCs a lot, including the lag induced by them.