[dheera]

> My leading cause of dropped phone, for instance is forgetting I have it in my shirt pocket, on my lap, off my desk, or from my back pocket if I don't put it in just right. Am I a different person in each of those circumstances? The statistical answer would be no, but only cones from widening the scope of collected data. Suppose I fiddle with it? Dance with it? Have a habit of leaving it in a car? Without a control,

Oh, but all of these can be added to your statistical model and learned over time! If we figure out that you suddenly walk with a limp, and all the other metrics match, we can recommend painkillers! Or if the other metrics match and you start dancing, we start recommending dance instructors! Hell, we can even figure out how well you dance using the IMU and recommend classes of the appropriate skill level.

For a recommendation system, like ads, the consequences of mis-indentification wouldn't be that high either. You'd still target much better than random, which is the alternative in the absence of fingerprinting.