I currently have no status on AA, and will take a flight going AAA-ORD-BBB tomorrow, where ORD-BBB is operated by ERJ. I tried to check-in online, but the system only puts me through AAA-ORD, but did not check me in for ORD-BBB, and I do not have a seat (seat map full). There are two more ORD-BBB later in the day, but both are also close to full (but still with empty seats on the seat map).

I want to know what will happen if I get IDB'ed from the flight. I remember that the IDB compensation for smaller aircraft is a little different. Will I get no compensation at all if I get IDB'ed? Thanks!