Don’t display html if function returns nothing

<?php
global $related_posts_thumbnails;
if ($related_posts_thumbnails->get_html()) { ?>

    <div id="relatedproducts">
        <h1>Related Products</h1>
        <?php get_related_posts_thumbnails() ?>
    </div>

<?php } ?>

A quick look at the get_related_posts_thumbnails() shows that it is simply echoing the HTML returned from the get_html() method of the $related_posts_thumbnails object. By checking the returned HTML first, you can make sure it is not an empty string (or any falsy value).

Note for the plugin author: picking the name get_related_posts_thumbnails() and making it echo the output is quite unintuitive. Other WordPress functions use the get_ prefix for functions that return data, and leave it out to echo it. For example: get_bloginfo('url') vs bloginfo('url').