['Been briefed' - she's so formal, more so than most people. But Hifumi doesn't have much room to talk, between erring on the side of politeness and her dramatics in the middle of a shogi game.]

I don't know that the locals know of one - they were surprised to see any of us at all, at first, and it's likely only the recurring pattern of new arrivals making it more rote as time goes on. Whether that means the reason is nonexistent or simply one we don't understand, I'm not sure anyone could say.