Originally Posted by MSPeconomist

This doesn't make sense to me, at least for the way USA credit cards work. Thai should be processing the refund through the credit card and AFAIK it wouldn't matter to anyone whether they give a "refund" in response to a chargeback or let the chargeback stand unless it somehow delays when they must pay. It they do the refund for some reason, refunding to the original form of payment means that the credit card account shows the refund, so it's easy to verify whether this was actually done or not.

However, if the ticket had been purchased with a combination of money, points, and vouchers (or gift cards, etc.), I guess they could refund just the money portion and the customer would need to go back to the credit card and try to "prove" (but it shouldn't be the customer's burden) that the points and/or vouchers weren't returned, but these items normally wouldn't be part of the chargeback anyway.