I love delta's policy or overbooking every flight, and then bumping people off at the last minute. Thus far, it has gotten us a total of 2.5 free trips in the past 6 months. You heard me. Free. Let me tell you just how dang good it feels to push "purchase" on a trip that you don't actually have to pay for. It's fantastically good. It's even better than when ma and pa pay because there's no associated guilt that you have somehow taken advantage of your parents' generosity. So the next time the delta people ask for volunteers, I recommend you push and shove your way to the front of the line. It's totally worth it.