It's not as difficult as you might think.
Currently Adult sites have
HTTP headers that indicate whether their content is adult rated.
There is generally very high compliance with this because the 'Adult Entertainment' industry is very very lucrative and they don't want blanket legislation.
It's this high business profitabllity that mekes me think this won't happen.
We've already seen U turns to business interests on cigarette packaging and minimum price alcohol.
I suspect what DC has forgotten in his haste is that many of the media Barrons that support him so strongly have discrete or not-so-discrete Adult Empires.
I can't wait to see the reaction on "Dirty-Reader's-Wive's-Desmond's" Daily Express and Channel 5!