If a user enters an address of http://sitename.com/login then they are automatically redirected to the custom URL that I've set up using this plugin. It doesn't matter what custom URL I use.
Entering http://sitename.com/wp-admin.php does result in a "Page not found" - that works as I expect.
Shouldn't accessing http://sitename.com/login also result in a "Page not found"?
I've found this to be the case on two separate sites.