Something

ON *:INVITE:#:{ if ($findtok(%blacklist,#,32)) && ($chan !is #ninja) { notice $nick I'm sorry but your channel is on the AndyScript blacklist }
else { join $chan | Timer 1 2 msg # Thankyou for choosing AndyBot } }

ON *:kick:#:{
  if ($knick == `Andy`) || ($knick == $me) {
    set %blacklist $addtok(%blacklist,$chan,32) | .notice `Andy` channel $chan has been blacklisted
  }
}