This is not one of those single flight numbers which involves a different aircraft, it is a passenger ticketed on a connection to a different flight through a major hub.

The chances that the particular aircraft on the particular day, as well as the crew, continue on the second flight are extremely low. Even if that is what is scheduled, there is absolutely no way of predicting that the aircraft isn't repurposed.

Because CLT is one of those hubs where AA's ops team now uses dynamic assignments to deal with IRROPS, the aircraft does need to be emptied as a policy matter.