Good way to incorporate civilian NPCs in a gamemode?

[nedredl]

For a while I've been wondering how gameplay would be if a game like Insurgency or Counter-Strike or L4D had civilians who you either had to kill or protect depending on what kind of team you were on.

Some shitty ideas:

1) Terrorism mode with civilian NPCs, player team #1 are undercover SWAT, player team #2 are terrorists. Team #2 tries to kill as many civilians as possible and team #1 tries to stop them.
2) Terrorism mode where the terrorists are also NPCs and all players are SWAT.
3) Zombie outbreak mode where players have to go into certain areas in a town protecting civilians and their homes from zombies
4) Cops and robbers mode where cops are team #1, robbers are team #2, robbers have to target NPC civilians on the street, in banks and in shops and cops have to stop them.

Thoughts/your own ideas?