for mIRC v6.1
Code:
on @1:TEXT:*:#:{
  if ($nick !isop #) { 
    var %x = $strip($1-)
    inc -u30 %i. [ $+ [ $hash($nick $chan %x,32) ] ]
    if (%i. [ $+ [ $hash($nick $chan %x,32) ] ] == 5) {
      ban -ku30 # $nick 2 Your kick message here.
    }
  }
}

Go ahead, jump. 100,000 lemmings can't be wrong.