And it's carried through, to the end where Frodo can't stay. IIRC, the explanation was something along the lines that he
was a ring-bearer, and all ring-bearers had to leave, but Sam was a ring-bearer, at least for a short while, but he got to stay. That's puzzled me; I think it might be a message about Sam's being untainted by the ring, even though in such close association with it for so long (much longer and closer than Boromir, for example). Your thoughts?