Will NPCs leave without their house?

Solution 1:

Right now they are passive mobs, walking around randomly and watching you from time to time like cows and pigs. When you destroy their houses, nothing will happen. I destroyed an entire village and the villagers where still there after hours.

From the Minecraft Wiki:

Villagers have the AI of a pig. This is probably a placeholder.

This shows how they interact with the player and that their programming probably defines that they won't despawn if you destroy the houses.

I read somewhere (can't find the source right now) that maybe the NPCs will be a community in a later update. If you kill one, all of them will turn hostile. I would like that idea, because right now (pre-release 1.9) they look kind of stupid. (Especially since the have male genitals in their faces.)