I would guess it depends on who lost money in the transaction. If the airline, then they will certainly try to recoup or cancel (depending on the size of the financial hit). It its a bank or financial institution they might not even notice it for while, if ever and then toss it out as a rounding error. Like the Argentinian Peso incident via Visa Germany last year.

Even if within the airline, if its not picked up by revenue management, chances are they'll notice this down the road.

As with many of the deals on here: Hope for the best, but expect the worst.