What I have to wonder is will AA get rid of the "flat tire rule" (albeit informal) and require that anyone checking in late (or too late to the gate) be forced to pay a change fee and refare. Based on the experiences I've seen of others agents have been willing to either put someone on the next flight or at worst make them go standby. Now in all of these cases they've shown up either right after cut off time not something like 3 hours late. But think of the additional $$ AA could make if they no longer allowed any flexibility.