function plt_hide_legitimate_post_submitter_metaboxes() {
$screen = get_current_screen();
if ( !$screen ) {
return;
}
//Hide the "Legitimate" meta box.
remove_meta_box('legitimate-fields', $screen->id, 'advanced');
}
add_action('add_meta_boxes', 'plt_hide_legitimate_post_submitter_metaboxes', 20);