I mean lets be honest if you are up to no good and there are facial scanners, you'd just throw on your n95 mask and black hoodie, maybe stick a pebble in your shoe, and then poof this tech no longer stops the bad guys.

There are also cases where law enforcement misuses this sort of technology to stalk romantic interests. So your kids could very well be stalked by a pervert in law enforcement more effectively with this technology.