I think what he means for the third option is this:
He may have
only just opened a chat window and before he's had a chance to say 'Hello' (or whatever) his parents (whoever) have walked in and he's had to revert to boss mode. Therefore, currently, the boss mode feature will send the predetermined text to all open windows (eg 'brb') including the window that has just been opened without any conversation having taken place. This means that the recipient will receive 'brb' and think 'wtf, I haven't even spoken to him'.
I personally think this will be difficult to implement and mainly useless as it would be such a rare occurance.
[Correct me if I got your idea wrong skootles
]