RCP: remove the metabox from the books and page post types

rcp-remove-metabox-cpts.php

<?php
/**
 * Remove the "restrict this content" meta box from the "books" and "page" post types.
 * 
 * @param array $post_types List of post types the meta box should not be added to.
 * 
 * @return array
 */
function pippin_exclude_post_types_from_rcp( $post_types ) {
    // We do NOT want the meta box displayed on the "books" or "page" post types.
    $post_types[] = 'books';
    $post_types[] = 'page';
    
    return $post_types;
}

add_filter( 'rcp_metabox_excluded_post_types', 'pippin_exclude_post_types_from_rcp' );