I don't see the point. If you want to be left alone, go to /busy and move along. You have LS, FC etc. to talk to those you want to while /busy.

We have a way of dealing with at least FC Spam: the blacklist. Someone stalking? Blacklist. Yea they can follow, but you won't see anything they type. Not perfect but we DO have the means to more or less accomplish the same thing.