Mine

on *:TEXT:@*:#: { 
  if ($me ishop $chan) || ($me isop $chan) {
inc %@ [ $+ [ $nick ] ]
    if (%@ [ $+ [ $nick ] ] == 1) {
      /kick $chan $nick First Warning : Don't use Public Messages.
    }
    elseif (%@ [ $+ [ $nick ] ] == 2) {
            /ban -ku300 $nick Second Warning : Don't use Public Messages. 5min temp ban.
    }
    elseif (%@ [ $+ [ $nick ] ] == 3) {
      unset %@ [ $+ [ $nick ] ]
      /ban -k $nick $chan Perm ban for 3 uses of @
    }
  }
}