Interesting. Well, I don't know.
I'm guessing it's a bug, but maybe Valve won't notice it if nobody tells them
Though of course, if everybody received 2 extra genuine items, their market prices will go down so fast, they'll be worth a lot less.
As for the conversation we had in the Shoutbox, the demo crown is indeed an old promo item. It's too bad, it looks great. They should bring it back!