Turn off trackback/pingbacks and comments on all existing multisite sites

This code was tested in a local testing Multisite. Seems ok, but found a minor glitch:
– after running it all drafts/pending posts disappear from the listing page, but appear again after a refresh, no idea why…

Although I believe it’s pretty harmless, please backup your database before running this

/*
 * Turn off trackback/pingbacks and comments on all existing multisite sites
 *
 * Important: Run Only Once, visit any admin page and delete/disable the hook 
 * 
 */
add_action('admin_init','wpse_55209_run_only_once');
function wpse_55209_run_only_once()
{   
    global $wpdb;
    $blogs = $wpdb->get_results("
        SELECT blog_id
        FROM {$wpdb->blogs}
        WHERE site_id = '{$wpdb->siteid}'
        AND spam = '0'
        AND deleted = '0'
        AND archived = '0'
        AND mature="0" 
        AND public="1"
    ");

    foreach ($blogs as $blog) 
    {
        update_blog_option($blog->blog_id, 'default_ping_status', 'closed');
        update_blog_option($blog->blog_id, 'default_pingback_flag', 'closed');
        update_blog_option($blog->blog_id, 'default_comment_status', 'closed');
        switch_to_blog( $blog->blog_id );
        $wpdb->set_blog_id($blog->blog_id);
        $allposts = $wpdb->get_results("SELECT ID FROM $wpdb->posts WHERE post_status != 'inherit'" );
        foreach( $allposts as $pt )
        {
            $my_post = array();
            $my_post['ID'] = $pt->ID;
            $my_post['comment_status'] = 'closed';
            $my_post['ping_status'] = 'closed';
            wp_update_post( $my_post );
        }
    }
}