Tribe 404 Meta=noindex Test

// This snippet adds diagnostic info to your sites <head> html comments
// If both is_404() & tribe_is_event_query() == true, it will output a noindex meta tag
// Tribe should be doing this already, but some plugins & themes strip these tags
// This function further tries to avoid stripping those tags by adding 100 priority to the action
add_action('wp_head', 'tribe_noindex_on_404', 100);

function tribe_noindex_on_404() {
    $is_404 = is_404();
    $tribe_is_event_query = tribe_is_event_query();

    $output =  '<!-- Tribe Index Test'."\n";
    $output .= 'is_404(): '.($is_404 ? 'true' : 'false')."\n";
    $output .= 'tribe_is_event_query(): '.($tribe_is_event_query ? 'true' : 'false')."\n";
    $output .= '-->'."\n";

    if ( $is_404 && $tribe_is_event_query ) {
        $output .= '<meta name="robot" content="noindex,follow" />' . "\n";
    }

    echo $output;
}