Good morning FP's. So I was thinking last night, how cool would it be if you where crafting in your house or base and all the sudden you heard a knock on the door and all the sudden an NPC opened the door and popped in to either kill you or scavenge your stuff. For one, you would have a better use for some PVE servers to have to lock the doors. Two, that would really just be freaky as heck to have an NPC open the door on you and walk in while you where innocently crafting away. Or how about coming home to find someone is walking around in your house because again... you didn't lock the doors. I think that would add a really freakish element and at the same time be very organic.
Other ideas would be to not have it only as a single NPC but maybe a party of scavengers, random time, setup to knock first, and then find other ways to get into the house or base.