As a developer and WorPress user I find this a potentional bug because some wysiwyg editor will change the dir to dir/ making the url erroneous for rendering as HTML request.
backslash "/" should redirect to directory!
so dir = dir/ server header should be 200 okay.
So request to "dir/" should return "dir" 200 okay!
Now using a redirect hack
This can easily be fixed as a url rewrite in .htaccess or apache config file.