It'd be a nice feature but the only way I can see it working realistically is a Hostage scenario, playable Civillians (like in PR) or some new Game-mode based around it. If you just had a Map full of AI NPC's, unless the server was very RP centric you'd probably just get people Shooting them on purpose. Programming AI that react's well and actually add's to the Game would probably be quite hard aswell, like if they just stand still and do nothing when a Battle erupt's around them it's going to achieve the opposite effect.   I could see it working if you had Hostage's and maybe some AI Civillian's in the vicinity (like getting Intel from them) then a Player having the ability to switch roles with the Hostage once found (like in ARMA where you can jump from character to character) as it'd be annoying if the Hostage got killed because they decided to just stand out in the open while the rescuers were all taking cover or something.   Actually, that'd make kind of a cool night Map  .