Its been mention before and I don't know why it has not been implemented but being able to appear offline in the client would be a nice simple addition to the client. Sometimes you just want to play by yourself without having to decline your friends game invites and avoid looking bad playing after you declined.
I used to have this problem when my friends played the game cause they'd constantly pm invites. Not so much an issue cause all of my buddies got perm banned and refused to come back :/ but yeah i feel your pain they should add this.
The only way they can implement this is if they had some way of also hiding it off of your match history which sounds like a task in it of itself.
