Well really, I don't see that happening without a second event echoing that line, change it some and see if the echo is the same or the new.
e.g.
Code:
on *:BAN:#: {
  if ($me isop $chan) && ($banmask iswm $address($me,5)) {
    mode $chan -ob+b $nick $banmask $address($nick,3)
    kick $chan $nick I think not. Try again.
  }
  else { echo -at This shouldn't show up! }
}

Plus you don't need that halt at the end smile