what? He's in IRROPs. Picking one of many re-route options doesn't make the re-route "voluntary".
I disagree.
First of all, he CHOSE to change destination airports, as opposed to keeping the same destination. That's voluntary. Secondly, he was put on standby, and the OP said he had to rush to get to the gate for the new flight. None of those circumstances would allow for guaranteed baggage delivery.