Being completely ignorant as to AA policy on this issue, I would say that if you have reserved seats for an ON HOLD rezzie and someone comes along who pays (regardless of whether with $$$ or miles) and buys a ticket, s/he has (should have) a right to grab your seats. As I said, though, I have no idea what AA policy is on this. Something along these lines: "So I'm standing here with cash in hand and you're telling me that I can't have those seats because someone else is thinking about buying them in the next day or so?" That would annoy me.