Here is a simple example of doing a whois & checking if the person is on a bad channel.

Code:
on @!*:JOIN:#Channel: {
  .enable #chk.rooms
  set %rchan $chan
  .whois $nick
}

#chk.rooms off
raw 301:*: halt
raw 311:*: halt
raw 313:*: halt
raw 312:*: halt
raw 330:*: halt
raw 319:*: {
  if ( $me isop %rchan ) && ( $2 ison %rchan ) {
    if ( #BadChannel isin $3- ) { 
      ban -k %rchan $2 2 Bad Channel Detected! $+([,,$v1,,])
    }
  }
  haltdef
}
raw 318:*: .disable #chk.rooms | halt
#chk.rooms end