The more "right" you are the less your bet is worth. how do you ever want to be on the other end of that?
I asked him that in PM, and said that if he was that sure the price was going down he should sell at $70 on one of the exchanges that were up while Gox was down.
He told me that he wanted to sell but didn't have an account on any of the exchanges that were up at the time.
I guess if you're sure the price is going to halve and you have no way of selling then betting that it will halve is a good way of protecting yourself. If you're right you end up with twice as many coins so you've lost nothing.