It makes me very nervous, but how "ethical" or not this depends on who's driving and participating in the effort.<p>A college friend of mine got charged with inciting a riot by standing on a car and shouting "Don't burn our hood! Go burn some rich folks stuff! Follow me!" According to him they didn't trash his stuff, and that was worth the hassle with the courts.<p>If your shop or car got torched or your kids are afraid at night, this is probably a great idea. Leveraging public data (photos) and off the shelf technology to at least identify witnesses if not actual participants should be done. If a friend of mine was in that situation and asked for help, I would do everything I could. If a company asked me to consult on designing the solution they could sell, I would probably pass.<p>I've been working in security, identity and privacy for over a decade and this "ethical" question has loomed since before Orwell. Commercial packages are marketed to law enforcement, today. Instead of disengaging or blindly sending your leads to police, the ethical middle path is a publicly defined framework. Using the riots as the catalyst, there should be public/web/community effort for vetting the most incriminating images, aimed at shaping the rules of public disclosure, law and evidence around facial recognition.<p>If this makes you queasy, get engaged. Saying "that's bad" or "they're wrong" won't stop those driving the technology solutions forward. Advocacy can keep the situation a little more honest.