Hadn't considered this interpretation before. But it makes me look at a moment in Act 55 in an entirely different way. A crying Ikuko tells Kenji: "It's so odd...I just...had a feeling Usagi's never coming home again..." (Kodansha translation) My original interpretation of that line wasn't literal. I thought she was picking up on the gravitas of Usagi's situation, even if she's in the dark on the specifics. But maybe a literal reading was intended.