Seriously, it drives me absolutely out of my mind. I tell everybody who listen, "Remember your users aren't software engineers who are always connected over fast reliable pipes, and program accordingly" but it's a hard problem. No PM ever wants to hear that you're spending time optimizing for no/low internet scenarios.

I've gotten burned by that "isn't really downloaded" thing a few times before too, to the point where I don't trust apps to download anymore. I just adb push files from my laptop to my phone before I go. Can't always do that though, but I try to.