I wouldn't think it's unethical, but it would suck to be the other guy sitting at home thinking about how hard it is to get an award ticket these days.
And comparing it to buying radios or renting a car or even a paid ticket is not really valid. Award tickets are few and far between anyway. And while it does happen, a store running out of a radio or Alamo not having a car is rare, and really isn't that big a deal. Who has ever missed going on vacation or visiting family because they couldn't upgrade their cd player. The concept in general applies, but only after a great deal of extending. I'd say it's more like blocking traffic in a car until you decide which way to go. There are ways around, they just may not be ideal.