In the new technical world today we have to be read for new technology. I would not mind constant monitoring by facial recognition systems because I have nothing to hide. I'm sure that some people would think that it is an invasion of privacy. I think that all depends though if you have something to hide.
Now, I do not think that everyone in the criminal data base should have to be recognized, in less they need to be located for some lawful reason. For instance, if you have more than one felony, I think you should be located and recognized. My reasoning for thinking that is because more than one felony is more than just a slap on the wrist, and obviously the first time you got into trouble you did not care.
If I was improperly detained due to a mistake by the facial recognition system I would be upset. But there are plenty of technical devices that make mistakes everyday in our world. Technical devices will never be perfect. So, the chances of the facial recognition system making a mistake are slim to none. But just as long as the problem was fixed while they were detaining me under false pretenses, I would just have to get over it. This is life and mistakes will constantly be made.