This is a bit hypothetical for me, but I do have an older relative traveling to the US in a few months, and I'm not sure she'd understand the retrieve check bags at customs process in the US. So my question is, say she's flying PVG-ORD-AUS on AA 289/2491, (i'll fly out to ORD to meet her) what would happen if she failed to retrieve her checked bag at customs and already left the customs hall? Would they let her back in to get it or would they have to send in an agent to retrieve it?

i'm assuming that few bag thieves will purposely steal someone's checked bags here since there is a chance it could be inspected...