The same document does say that a path that contains slashes "these must imply a hierarchical structure".
My web sites are collections of pages (with a hierarchical structure). Every (ok nearly every) request for the domain loads the same file. The path is merely a database identifier (and every one is unique - fewer canonical issues than a web server's interpretation of a file system). Why should I use file system conventions?
[edited by: Status_203 at 9:59 am (utc) on Mar 26, 2010]