A rapid but odd response came today in the form of a support doc from Apple about the Do Not Disturb bug in iOS 6 that cropped up on New Year's Day (or Hogmanay, if you're Scottish). Apple published a KB article which is pretty brief on information. It says after January 1, 2013, DND mode stays on past the scheduled stop time, and that it will resume normal functionality after January 7th. Till then, stop using the scheduled bit and do it all by hand.
This is a bit of added insult to injury for Apple, who just yesterday debuted an ad showing off this very feature, one which no doubt got a lot of attention last week as people started setting up their iOS-based Christmas gifts.
Since I love a good theory, go ahead and list your craziest conspiracy-ist theory about why this is happening as of January 1, and what magic makes it disappear on the 7th in our comments.