Please set up a redirect to the canonical URL. This is helpful to third party systems that interact with your site, such as search engines and content sharing sites. It also eliminates the issue you raised.
When there are two articles with the tag, they will both be shown on the 'publishing' page, in their entirety, newest first. See [1] for an example.
Redirecting would be akin to Google redirecting you to the current top result (like I'm feeling lucky, but for all searches)
Anyway, I didn't mean to argue. Have a nice evening :)