> I think it is a best practise.
I agree that it would make things more secure if it were a best practise. However, it is currently not. Nobody actually does it, and I think you'd be fighting an unwinnable uphill battle to change this.
If you're going to fight this, you might as well deprecate the CA system as best practice while you're at it. Does this sound unlikely? The same problem applies to asking websites to publish a suitable warning.
And how would you securely broadcast such a warning, anyway?
