Tell me please...
...how much does it cost to follow 1000 people 24 hours a day. On the other hand, how much does it cost to write a naff but possibly catchy game, and give it away free to 1000 iPhone users?
As far as stealing your phone; you'd notice that, but what has been reported is that there is a file on your phone, and they don't have to steal your phone to read it.
Also the fact that they can decide to "follow" your movements AFTER you have made them. How much does it cost to follow someone afterwards (what's the going rate for a time machine these days?)