It's like nuclear power, technology is what we make of it. Do we want to use it for criminal purposes only, effectively to almost make it impossible for someone to commit a violent crime and get away with it and make a much safer society? I'm all for it, there are some nasty people out there, serial killers, pedophilians, drug cartels. This technology deployed at scale would make these crimes much harder to get away…
Ski mask. You might catch/convict a guy with it, but soon after a lot of people are just going to wear them all the time.
I also foresee a surge in wide-brimmed hats.