Yes, return has the same effect with no parameters. Also, if your going to have a condition (though you won't notice speed) it might be easier to have the condition to catere to you.
Also, I saw you have a capital 'B' for the banmask move. In almost all cases, this is lowrcase, and most IRC servers are case-sensative.
#onban on
on @*:BAN:#:{
if ($nick != $me) {
if ($banmask iswm $address($me,5)) {
mode $chan -b $banmask
chanserv unban $chan $me
echo $colour(info) -a *** You were banned By $nick on $chan $banmask
}
}
}
#onban end
