External page url ignored, when page accessed directly

Each page, created under "Structure & Data" section can either be located on In-Portal website (default option) or redirect user to any other url (external url) on other website. When external url is specified, then In-Portal displays specified external url instead of internal page url.

However recently I've discovered, that I'm still able to access internal page url (even of website don't display a link to it), when it's external url is specified.

I think, that we should process such case and perform "Moved Permanently" redirect when old page url is accessed.