So far people are objecting to the police knowing who you are, wait until criminals get hold of this. Any tech like this will leak out over time. Muggings already include a mandatory chip and pin check, add a fingerprint check too and life can become miserable very fast. Easy to change a pin, hard to change biometrics. A marketplace for fingerprint scanners, fingerprints and facial scans is likely to arise from the wide adoption of these technologies.
Pushing the domain of scanning into unregulated space (ie: the wide world) makes it a lot harder to check a scan is legitimate. Once facial scans and fingerprint scanning is in the public space then targeted criminal activity becomes a lot more feasible, especially if the police maintain their current approach to data retention: ie - too long. They are too focussed on legitimate use rather than the ways criminals will abuse their own tools. I am sure there is some irony in there :)
Witness protection just became a whole lot more complicated too.
Biting the hand that feeds IT
