Why do you say that? Did you watch the whole thing? It doesn't seem "unclear" at all. There are whole classes of explosives that the devices won't detect at all. Whether it actually would have detected the underwear bomber is actually less important. Here is real evidence that the machines don't work for the main purpose they were being sold on. The pro-scanner spokeswoman was even forced to say that no device is perfect. The devices don't work, plain and simple. The only thing left to see is whether they really can detect ceramic and FRP knives, which would be the sole point of these devices.