Simply put, my iPhone's GPS appears to be unable to figure out where I am when I want it to (when I'm at home it usually puts my location out in the estuary near Coast Guard Island; apparently I spend a lot of time on a boat. Or floating). Using it to navigate around a city with it is fraught with peril (the other day I was trying to find a small street in the Bayview -- I was only a couple blocks off but just wanted to know whether to turn right or left -- and it insisted I was in the Richmond). Even when it does by some miracle place my location roughly correctly -- say, within a block or so -- moments later my locator will jump a half mile in another direction as if I were driving a quantum vehicle.
I'm sure it's some freak thing about my phone, since this is not something my friends with iPhones complain about, but basically, if somebody were to steal my phone and download my location, they'd get a set of locations that are exactly NOT where I ever go. So good luck with that.
