Why Sunfish are you almost the only pilot out there who believes that you still need to carry paper maps with you when others have long since moved on?
I carry paper maps. I'm a software developer, and I do not trust PC, Ipad etc. software enough to rely on them as a sole source.
Have you turned off automatic updates on your Ipad? If not, there is no guarantee that your software works the same tomorrow as it does today (or works at all) after connecting it to e.g. the hotel wifi. I have seen enough apps with major problems after updates to be very wary.
Incidentally, I also agree 100% with Sunfish's original points. They should be printed out and stuck on every software developers wall.