I'm going to assume that Michael and Kay wanted the drapes closed all that day because the party attracted thousands of guests, many of whom would wander around and probably want to peer into the house out of curiousity. Kay might have made a point of telling the staff to keep the drapes closed all day. It does raise the possibility that someone on the staff was in cahoots with Roth or his representative. But I doubt Roth would have reached that far down--it'd be too unreliable. Fredo's still my choice.