Originally Posted by
paterwdb
Is this true specifically because it is a refund? Because when I've canceled a non-refundable after taking the outbound, I've been given a credit for the remaining segments (typically half the fare paid, not the fare minus the one-way published fare). If that is true, it would make sense to book it as non-refundable and take the credit.
Much depends on the route. For lots of domestic USA travel, most or all fares now are one way (somewhat to match WN etc. fare conditions), but put together on a single ticket/PNR to look like a RT. For lots of international destinations, OW fares are extraordinarily expensive. Airlines obviously don't want people to evade the RT requirements (price discrimination) by purchasing a RT ticket and then getting a refund for half of the RT fare paid.