Prime example would be the Alinor Crest Townhouse. The terrace overlooks the crafting area, which should be bustling with activity. Yet...it's completely devoid of occupancy.
I get it's instances so I don't expect to see players running around down there. But there are NPCs in that area, why not put them in the instanced version of the area they normally would inhabit if I were to walk into that area?
From what I can tell, these out of bound areas aren't "cardboard cut outs" arranged to look three dimensional. So, it should be as easy as placing the NPC and loading it's normal routine script that works to give life to the game's world, even if players aren't present.
You have to learn the rules of the game. And then you have to play better than anyone else.