I don't know why, but for some reason neither
child_of are being accepted as arguments in
get_posts that I'm using a
$sidebarReviews = get_posts(array( 'child_of' => get_ID_by_slug('testimonial-reviews'), 'orderby' => 'rand', 'posts_per_page' => '6', 'post_type' => 'page' ));
get_ID_by_slug is a custom function I have just to translate slugs into page IDs. This is working correctly.
However, when my foreach runs, it seems to pick up every page that's in my Wordpress database.