Re: How about...
But most websites don't need this level of functionality. The time and effort involved to update a minor site for a local club or something is not going to happen.
If the functionality is needed then yes some sort of warning, but something that complains about EVERY website that is not up to latest standard (and that is a nebulous thing to describe) is going to get ignored and just annoy the user, so that they won't use the browser that flags it and will go to one that doesn't
