Team BLD: I think there are too many logistical issues. How do you hold paper in such a way that the caller is not obstructed but the solver is? There would have to be a very rigid rule about what kind of paper is allowed and where it can be held. How do you deal with the fact that competitors can impede each other by calling very loudly, which can actually be argued is proper solving strategy? That would be both a problem to competitors actively competing and an unfair advantage to people who haven't gone yet and get to hear the entire solve before doing it. I think expecting organizers to find different corners of the room, or having all competitors go sequentially, is way too much of a burden for organizers.