Originally Posted by
bocastephen
These are designed to be used on smartphones, not iPads - the airline will give you the option of displaying a mobile boarding pass, usually by an email link that you click. It's not a PDF copy.
Well, one could make a PDF of the mobile BP (I've done this). However, your point is correct and important; a PDF of a normal BP will not work. Mobile BPs are "special".
I use an iPad for these all the time. The only problem I have is with the CO gate readers, which don't have enough room for the iPad if the barcode is centered on the screen (the HTML version has the barcode in the corner, so it works fine).
I've even used a Netbook for mobile BPs without problems.
One thing I always do is get a screen shot (center + power buttons on iOS devices) of the mobile BP so that I don't need an internet connection to display it.