>what should happen when some objectionable people would access a site what doesn't have anything in the site metadata?

>what should happen when some very objectionable people would access a site what do have all the required data in the site metadata and they would still complain?

Nothing; publishers on the internet don't owe anyone anything, but that doesn't mean they can't try.

>Also you are clearly missing the usual "think about the children" drivel.

That is always going to be a battle; I don't think this suggestion is a meaningful paradigm shift in either way. One could argue that this satisfies the needs of the "TATC" crowd, because it puts the control in the parents hands, via browser, and is therefore a less centralized solution.