It's made somewhat clear, but is easily missed, in the Japanese version of the Anime. In the episode where they take her on board, Faye mentions it in the last scene before the credits (have to rely on the subber though). This was used in the German translation, but if I remember correctly, the sentence is missing completely from the English version. But really, I agree, Ed's just Ed.
I had a friend, who studied history with an emphasis on Japanese culture, harp on at length about the specifics of how Japan treats these things and how it made more sense in that context and was somehow a significant thing, but I admit to having forgotten over the years.