Doesnt make sense why they would allow it to be advertised on there. Did Blizzard fix that problem?
But the ads which appear are not really defined by them, obviously they can choose to only advertise under eighteen stuff. Besides, the ads that come up through google/adsense tend to be engineered to whatever the IP was viewing earlier, I'm consistently getting adverts for Vista office cards just cos I had a browse of the site a few days ago.
And I doubt the site which is being paid host the Advert frame, which all the ads are displayed, would be party to prosecution, or responsible, but rather who ever the advert directs the user to.