Do you guys think most of the people who are crying for Appear Offline mode are the people who play too much but dont want people to know they do?
They make up some stupid excuse that they don't want to brush people off but its not that hard to put your status on Do Not Disturb and if they message you just say can't talk busy.
In real life they probably tell their friends they go out to parties and all this cool stuff everyday, so they want an appear offline mode so they don't get caught on WoW when they suppose to be "out".
Also if blizzard adds the feature appear offline then valentines day you will probably hear everybody say they have a hot date and wont be "online" but they will just be in appear offline and you will probably catch them gathering herbs.
Its not that hard to tell people you are busy if they get angry at you for being busy why don't you just delete them from your friends list?