Allow unlimited votes from authenticated users?

Is it possible to alter the poll module to allow an authenticated user to vote an unlimited amount of times on a poll??? I know this is a rare request, but in my situation multiple students share one account and would like to each get a chance to vote.

I tried altering this section, but I guess it's more complicated than that because I got an error

  // Determine whether or not this user is allowed to vote.
  $poll->allowvotes = FALSE;
  if (user_access('vote on polls') && $poll->active) {
    if ($user->uid) {
      $result = db_fetch_object(db_query('SELECT chorder FROM {poll_votes} WHERE nid = %d AND uid = %d', $node->nid, $user->uid));
    }
    else {
      $result = db_fetch_object(db_query("SELECT chorder FROM {poll_votes} WHERE nid = %d AND hostname = '%s'", $node->nid, ip_address()));
    }
    if (isset($result->chorder)) {
      $poll->vote = $result->chorder;
    }
    else {
      $poll->vote = -1;
      $poll->allowvotes = TRUE;
    }
  }
  return $poll;
}

any help is appreciated!