Well, a "not-very-cool" way to check if someone is offline or Appear Offline:
Create a new email account, and add that person on your new contact list. Then check if they have added you on their list. Another thing that I have observed is that when you add someone who is on Appear Offline, then by the time they accept you invitation their nickname changes from the address to the nickname (if they have a nickname instead of the email address).
Of course that person must accept your invitation. But I think that most of the people do accept in order to see who that person who added them is.
If that person is on Appear Offline but not in front of the computer at the moment or is indeed Offline and you can't wait in front of the pc to check what happened, use the Event Log. See if they've come online at all and if they have added you to their list.
Of course this is not the best way to check everytime....but it is something anyway!
