But this is something clients can actually do today, without the need for a new protocol or any awareness on the server side. URL isn't HTTPS? Don't load it. I

But this is something clients can actually do today, without the need for a new protocol or any awareness on the server side. URL isn't HTTPS? Don't load it. I actually did a Firefox plugin that implements this, called http-nowhere. Yes - and my understanding is that the browser developers are going to require all HTTP2 connections to be over TLS anyway.