If you are reffering to when a user joins, that event gets directed to another alias. This alias runs when I join a channel and subsequently get opped. The rawmode event detects when I've been opped with either mode +a or +o [ I did it that way because "on *:op: #:" does not detect when I am opped with a '!' (mode +a) ]
Once I'm opped the alias cycles through every non-opped users address looking for a match and acting on those it finds.