I know of scripts or bots that will send a message to people leaving the room.
That message ends up in the status window.
As far as i know that is done by a /notice.
here is the code:
on !+1:PART:#:{
set %target $nick
set %place $chan
/timergreet 1 3 /notice $nick $read $mircdir $+ part.txt
}
Hope this helps
Greetzzzz