Document Library issues - Duplicate file names

Came across an issue with a content editor yesterday. We've solved it, but seems to me there should be a way to prevent it from happening.  Here's the situation.

She uploaded a document via the html editor by creating a link. It named the document "Categories" (the text of the link). She then went into the backend  under the Library module and renamed it something more descriptive like "Advertising Contest Categories".  However, the "Use multiple URLs" automatically checked to redirect all requests for the document named "Categories".

A day later she uploaded a new document "Newspaper Contest Categories" using the same process and so the document was named "Categories" (the text of the link). However when anyone visited the page, they were getting the Advertising Contest Catgeories because the Use Multiple URLs was checked, redirecting everyone to that document, even though a more recent document (completely different) document was allowed to be uploaded with that name.

So the issue is that content editors are allowed to upload documents with file names (urls) that already exist with the Use Multiple URLs option checked.

We are experiencing the same issue -- the system allows different documents in the same library to receive the same URL. It then seems to be somewhat random which version of the document is displayed when someone visits that URL.

Because we have a large number of users who upload to our site, we're also looking for the solution that prevents this from happening in the first place. At the moment, the workaround is not intuitive for a very basic user and can create a file management nightmare in the back end.