I would imagine that a one-way hash of perpetrators’ faces would be fine (taken at time of infraction in lieu of charges being filed). Then, you simply create hashes as people come through, and remove the hashes if there isn’t a match. As long as you aren’t storing hashes or images of the non-perpetrators, it seems less obtrusive. Knowing someone’s face print for less than a second seems fine to me as long as it’s 100% wiped immediately. How -should- stores deal with offenders?