For decades people tried to correlate gait to personality and behavior. Then, DNA, with IQ and all sorts of things. Now they're trying it with barely-noticeable facial features, again with personality traits. But the research is still crap bordering on woo, and barely predictive at all.
It's at least plausible that we are sufficiently complex that, even with tons of NSA and corporate data and extremely sophisticated models, you still wouldn't be able to predict someone's behavior with much accuracy.