For the purpose of this question, I would like to highlight the following URL:
Upon selection, you will be successfully directed to a page displaying 'Birthday Gifts'. Something, you would probably expect; based on the URL.
Now remove '/birthdays/' and press enter. You will be taken to a variant of the
404.php page. I have come across this, quite often. Where a URL will be working fine but if you 'go up a directory', you will land on an 'error page'.
Firstly, why do websites not resolve this? Is this some kind of strategy, which I do not see here?
Secondly, how is the page to the right of the 'error page' still able to load, if the 'parent page' is non existent? I do not know if I am just used to Content Management Systems, such as WordPress, but shouldn't a URL be redirected, if the 'parent page' is non existent?
Speaking more broadly, couldn't this undermine SEO efforts; based on user experience? I would assume, this URL structure could result in a 'broken' breadcrumbs. Furthermore, isn't a visitor's ability to navigate via the URL directly also considered a positive user experience; albeit small weighting?