I also just noticed that you didn't add a kick event either.
Code:
alias CheckIdlers {
  [color:blue]var %chan = #YourChannel, %a = $nick(%chan,0) [/color] 
  while %a {
    if ($ulevel != 10) || ($ulevel != 11) {
      if ($nick(%chan,%a,r).idle > 20) { 
        ban -ku300 %chan $nick(%chan,%a,r) 2 [color:blue]| kick %chan $nick(%chan,%a,r)[/color] Please do not idle. Return in a while if you need help or want to help 
      }
    }
    dec %a
  } 
}


Those who live by the sword get shot by those who don't.