It's virtually no mafan at all, actually, but we already support it through the "Share Files" command in Settings - Apple just added an official way to do the same thing. (we were piggybacking on their code for local game networking before, but the same basic protocols in any case)It would be cool to be able to share individual decks (flashcard categories) to nearby friends, if the API for this new feature isn't too mafan... Maybe in the version after next?
One thing to consider is that AirDrop—mystifyingly—won't work on the 3rd gen iPad, the iPhone 4S or the 4th gen iPod Touch. It'll be at least a couple of years before developers can rely on it.