sometimes its that you know a person or a scenario so well that, you know expression or communication of any sort won't have any impact . I feel communication should effective. It is kind of similar to how you should convey something only one time, when you are managing a team, so that all of your communications are novel and has impact.
Yes there are times when you know its best not to communicate but that's a different scenario. I would called that more of an Effective communication which would be quite different to a suppressed communucation which we are talking of here :)