The machines sit inside the security checkpoints and if you swipe your credit card you can get an iPod, headphones or anything else fairly small.
The big idea is that you can buy the gear to take on a trip or as a last-minute present if you forgot to get your spoilt child something during your travels.
You can't get a 42-inch television, of course, and if someone sees you pounding on the vending machine because it has not delivered your iPod, you could be shot by nervous security guards.