Yeah I think it depends how valuable you are to the organization. It's in their interest to pay you as little as possible, even if they're willing to pay more. I've negotiated raises before when I liked the environment and they never let me go or made attempts to.

On the other hand another guy did about the same and said he had another offer for more and they said they didn't want to lose him and matched the offer he supposedly had. He then thought he was invincible and started not showing up. About two months after that raise he sent an email out to the whole department saying that if you want a raise all you have to do is threaten to quit, and then that afternoon he threatened to quit again without another raise (again 2 months after the first substantial raise). They escorted him out of the building.