Localization duplicate page problem when locale set in routes

jameslittle, thanks for the hint. Both of our questions are successfully resolved by this code in routes.php:

PHP Code:

// localized routes
$supportedLocalesWithoutDefault = array_diff($this->config->supportedLocales, array($this->config->defaultLocale));
if (in_array($this->request->uri->getSegment(1), $supportedLocalesWithoutDefault)) {
    $routes->get('{locale}/books', 'App\Books::index'); 
    //other localized routes
} 


First of all we define all locales without default. Next we set localized routes only for this locales. This allows us to leave familiar URLs for the default language, and excludes access to invalid duplicate pages.

Anyway, it looks like a crutch, think decisions must be released in core