Spotted this beauty on a video streaming site:

  <a role="link" aria-label="play" tabindex="0" style="padding: 5px;">
    <button tabindex="-1">Play</button>
  </a>

This is failing the rule because the link is considered to be largely obscured by the button inside of it. I think the solution here is that when we check for obscuring elements that we exclude descendants of the widget.