Baggage Fee on Reroute
 

First off - this didnt happen to me but i witnessed this happen right next to me:

On 1/9, a lot of us coming in on UA881 missed our connections. UA rebooked me and another guy to a VN flight to SGN for the next morning, but they arranged for our bags to be transferred so we did not have to pick them up. These were connections originally and not a stopover in NRT.

Next day when we went to check in with VN, they asked if we had any bags checked. I had one and they confirmed it was on the flight. The other guy had 3 (UA Plat) that he checked for free in the US. VN made him pay $150 right there or he couldnt check in.

So here is the question - shouldnt he not be charged? I thought baggage fees (according to IATA rules) on US originating segments (which this still was) are all handled based on the rules of the initial carrier. Even if you went with international rules, it is still the case of the most significant leg - which would be ORD-NRT since it crosses a full region rather than a subregion? How would you have handled this one? I told him to just pay (since he wanted to get to his family's wedding), keep the receipt, and hit up UA for a refund when he gets home. That, I figured, was his "safest" option vs fighting it and missing another flight.

Thoughts?

You provided him with the best advice.

I had this problem in a domestic flight (UA flight cancelled, routed on DL instead, paid $35 baggage fee). Submitted receipt to UA and they provided a VISA gift card for that amount. I assume something similar would happen here.