==Hoods and glasses only work if everyone is doing it. In certain parts of my town you can tell the drug runners by their "uniform", primarily pulled down hoodi

==Hoods and glasses only work if everyone is doing it. In certain parts of my town you can tell the drug runners by their "uniform", primarily pulled down hoodies and a hand down their trousers.== I'm not sure I follow your logic. Your experience seems to prove the point that pulling a hoodie down helps conceal your identity, I assume that is why the drug dealers do it. The focus of the article is facial recognition, which is commercially available today. Your examples all require some type of initial identification to know where to check for someone's mass, scent, DNA, etc.