on *:TEXT:!rules:#: {
  var %r = $nick 
  .play $nick rules.txt 1500
  hinc -mu300 Rules %r
  if ($hget(Rules,%r) = 1) { 
    msg $nick *** Be warned that you can't use the !rules command more than once till u leave/quit.
  elseif ($hget(Rules,%r) = 2) {
    kick $chan $nick $+ , you've been told to only use !rules until you have parted the channel. | hdel Rules %r

The above script will count if a user triggers !rules more than once within 5 minutes, and if he or she exceeds the time allowance, they'll be kicked.