My suggestion is: don't get kicked in the groin!

I fly cameras almost as expensive as the N900 (which costs about US$ 500 in the US, according to a quick search). I managed hundreds of flights in 5 years, and until today I never had a crash. It almost happened once or twice (when the wind suddenly died), but even then, it was not free falling and the rig that holds the camera would have absorbed most of the impact, if not all (it is designed that way).

I can understand that... but as I said before, flying the phone on a kite is, for me, way more fun than selling it!

Nobody can guarantee that. There are risks involved (in anything we do, right?), but if you manage them well, you minimize the chances of an accident. And if there were no risks and no challenges, it would not be as fun and rewarding, too.