&gt; I&#x27;m not sure how they intend to circumvent this problem, apart from perhaps just instructing users to not use those browsers? That&#x27;s quite difficult to put into practice.<p>Even if pins overrode locally installed certificates, all they would have to do is to block all outgoing raw HTTPS traffic. All these browser-side security mechanisms can do is to refuse to initiate insecure connections (and inform the vendors about broken pins). They can&#x27;t force a network that is actively designed to forbid private connections to allow them.