Frogatr: The fine is in dollars here and not yen. How odd.
UrsusArctos: Although the out-of-universe explanation is that they just copied the entire warning from an English-language warning sign in the US, I don't know what an in-universe explanation would be for that. Perhaps dollars are being used here due to this being, technically, a U.N. facility? A hidden comment by the show's creators on the perceived American dominance over Japan?