I don't know how that'd work. When I put in any name, for example 'Paul', I'm brought to the URL 'https://www.youtube.com/user/paul'
I don't think it's a URL problem, since the name is just added to a pre-defined URL. 'https://www.youtube.com/user/*name*' More like an entry problem. I just can't enter numbers in without an error popping up.
But, like I said, this is totally not important at all. Very minor. Just me being weird.