A former employer used to tell the story of trying to sell facial recognition to the country's federal security service. They set up in airport with a list of 1,000 faces they wanted, and started scanning passengers. When they finished the first thousand of them, they were very very disappointed: that had got a huge number of false positives...
For each of a thousand people, they did a thousand comparisons. That's a million comparisons. Even if the error rate was only one percent, 1% of a million is 10,000 errors. In other words, it reported a false positive (or, horrors, a false negative) for everyone. When it identified someone's grandmother as a male member of the Baader–Meinhof gang, they packed up their equipment and slunk away.
Facial recognition is a guaranteed fail for airport security