Comment entry screen shows even though “Allow Comments” is unchecked

As far as I remember main purpose of comments_template() is to load template and specific logic should be handled inside that template.

Snippet from Twenty Ten comments.php:

if ( ! comments_open() ) :
?>
    <p class="nocomments"><?php _e( 'Comments are closed.', 'twentyten' ); ?></p>
<?php endif; // end ! comments_open() ?>