Okay, my original comment was probably more vague and snarky than HN deserves, so let me elaborate on my thoughts: 1) This will develop to the point that someo

Okay, my original comment was probably more vague and snarky than HN deserves, so let me elaborate on my thoughts: 1) This will develop to the point that someone sues over this, but gets smacked down because it's based on publicly accessible information. 2) It underscores that current jurisprudence is out of line with our intuitions about what constitutes norm-violating invasions of privacy. 3) Yes, it would be absurd to expect others to shield themselves from noticing your gait. But the problem is, like with all the other things we don't have an expectation of privacy in, it feels a lot more invasive when it's collected by a machine and aggregated in the large and correlated with every other data point about you. Jurisprudence, in America, doesn't seem to have a language for capturing that and so doesn't recognize it. (Heartbeats, for that matter, are something humans don't directly observe by default in normal everyday encounters.)