[TECK]

ya, you are right... i added this to the file.
in showthread.php, find:

  $textareacols=gettextareawidth();

replace it with:

  if ($bbuserinfo['emailnotification']) {
    $emailchecked = 'yes';
  } else {
    $emailchecked = '';
  }
  $textareacols=gettextareawidth();

in template showthread_replybox, find:

<input type="hidden" name="email" value="">

replace it with:

<input type="hidden" name="email" value="$emailchecked">

now it will look in your default preferences, all done in the background, so there is no need for an ugly extra checkbox. if you have it set to automatically recieve email notifications, that change will allow you to do it from now on.
for those who installed the hack already, just change the code listed above.