title: URL Slugs: Redirects or 404s?
body: <p>Some sites, like here at SO, allow 'bogus' slugs in the URL. Before implementing URL slugs on my site, I have a question of 'best practices'... </p>
  
  <p>Given a structure like <code>example.com/123/article-slug-here/</code>, if my site allows bogus slugs by querying on the ID - </p>
  
  <p>Should I ...   </p>
  
  <ul>
  <li>just do a redirect to the appropriate/canonical URL (verifying the slug, and redirecting in case of a mismatch)?  </li>
  </ul>
  
  <p>-or-  </p>
  
  <ul>
  <li>return a 404, since technically <code>example.com/123/this-article-s-u-x</code> doesn't exist?</li>
  </ul>