Out of curiosity, what happens when you use a mobile BP, but then run into an issue of your miles not being credited and the airline (esp an alliance partner that you weren't flying, but were crediting miles to) is asking for a copy of the BP? Since the BP is hosted on the airline's website, I assume it expires after you take your flight.

I thought about it when trying to claim miles on QF after I flew on AA. QF was requesting a copy of my BP. I used a regular BP, not a mobile phone one, but the thought did occur to me.