Originally Posted by
Often1
On a non-refundable ticket, the sale has been made and the ticket used. All of the government taxes (including things called "fees" imposed by the government) have been collected and paid by UA to the appropriate agency.
But clearly this is not so for refundable fares, because then you get your taxes back. Further, even on non-refundable fares there is a mechanism for UA to refund the taxes, because that is what happens when there is a cancelation caused by the airline that results in a refund.
I find it very unusual that a taxing authority would set its laws and rules for collection and remittance based on the policies of a private enterprise.
I think the OP may be on to something.