The only downside to two one-ways is that if you are booking penalty fares and you need to make a change, you will pay a change fee per ticket. Thus, moving a trip by a week out and back would generate a $200 change fee on a typical domestic penalty fare, while changing two one-ways would be $400.

While your wife would not be entitled to Gold benefits, she might still receive some of them. Thus, consider exactly what it is that she wants and cares about and whether that is worth it.