First and foremost, statements that can not univocally be established as either true or false at a certain point in the future are BadBets and as such unacceptable on BitBet. For instance, "God Exists" is unacceptable, because it can never be established as either true or false. "God will change Coke to Pepsi on August 19th, 2013" is also unacceptable, also because it can never be established as true or false (even if the change of Coke to Pepsi could allegedly be established).
The "advertised performance" can't be univocally established to true or false. The rest of the bet can be. That should yield two possible outcomes: a) The bet is cancelled because it's against your policy OR b) the bet is resolved on the non-ambiguous parts of it to "Yes".
My old "Yes" payout address is still valid.