I think these iPhone apps are in the same ballpark as arrangers, in a way.
Are you really MAKING music, or are you simply finding complicated ways to play back music that someone else has already made? This also folds back on the other thread we had recently... what exactly IS a 'musician'? Does playing the radio make you a musician? I mean, you turn it on, and out comes music! So, doesn't than make you a musician?
The iPhone thing. You shake it, out comes music! Guess that makes it a musical instrument, and you a musician, doesn't it?
But, by extension, think about this. You turn on your arranger, cue up an intro, and hit the C note. Out comes music! But are YOU being a musician, at this point, any more than someone turning on the radio? Sure, get past the intro, then you can play a melody. But consider this. Your melody is ONE note at a time. The accompaniment, the thing that takes maybe one finger to produce, is dozens upon dozens of notes that you had absolutely nothing to do with (or at least, most of you!). Are you still playing the radio? And whistling along with it? Or are you making music..?
The line gets blurrier and blurrier, more ill defined day by day. Once upon a time, every single note that the audience heard, they KNEW it was made by the people on stage they were looking at. Now, it's a whole different game. Some guy in London or Tokyo or Florence played 90% of what they are listening to. But we take the credit for it. Are we much better than a guy waving a PDA around, 'claiming' he is making music?