Mine

on $*:TEXT:/^[!@]whois?(on)?$/Si:#: {
  if ( $nick isop $chan ) || ( $nick ishop $chan ) {
    set $+(%,whois,$chan) on
    $iif(@ isin $1,msg $chan,notice $nick) 2Whois is now 7ON 2for7 $chan $+ .
  }
}
on $*:TEXT:/^[!@](whois)?off/Si:#: {
  if ( $nick isop $chan ) || ( $nick ishop $chan ) {
    set $+(%,whois,$chan) off
    $iif(@ isin $1,msg $chan,notice $nick) 2Whois is now 7OFF 2for7 $chan $+ .
  }
}
ON *:JOIN:#: {
  if ($($+(%,whois,$chan),2) == on ) { 
    set $+(%,whois.,$nick) $true | whois $nick
  }
  elseif   (%whois [ $+ [ $chan ] ] == off) { halt }
}
raw 319:*:{
  if ($($+(%,whois.,$2),2))  msg $ifmatch 7 $2 2is on 7 $gettok($3-,0,32) 2Channels: 5 $3-
  unset %whois. [ $+ [ $2 ] ]
}
}