Comment signatures

I was just reviewing the code, and came across this highly puzzling snippet in comment.tpl.php:

<?php if ($signature && $comment->cid > 3443): // The highest comment ID before upgrading to Drupal 6 ?>
    <div class="user-signature clear-block">
      <?php print $signature ?>
    </div>
  <?php endif; ?>

If I read that right, it won't print out a signature on any comment with an ID of less than 3,444. What? Why not? The "highest comment ID before upgrading to Drupal 6" comment makes me think maybe this is a site-specific workaround, in which case it should be removed. Or if there's a good reason for keeping it ... could you please explain what that reason is? 'Cause I can't think of any.