For what it’s worth, I went through the airport in San Diego recently. It does have a sign mentioning that facial recognition was present and the photo would be deleted immediately after verification but you could opt out. It’s up to you to believe if that’s true or not. I’ve already accepted the fact that there’s cameras everywhere in airports and the government has my biometric information anyway so it’s futile, but there’s nothing wrong with opting out of biometric checks if you have the option.