It actually worked fine on both an Ipad and an Ipod-Touch.
The TSA scanner is different of the one at the gate but if the scanning at the gate fails they will print you a paper copy on the spot. My concern was with the TSA as once you are admited in the sterile zone , they will let you board the flight even if you have no boarding pass, like i just said before.
I flew with my wife so we had to use two different devices (even though I believe they would have admited both of us on the same device)