“Everyone, regardless of citizenship, can opt out when it comes to domestic flights in the US.”
The TSA wants facial recognition in all of the more than 430 airports it covers, and over 80 already pilot it. Opting out is legal, but the signs are tiny and passengers, a senator among them, have met resistance when they try. Foreign nationals on international flights mostly can’t refuse at all. The TSA sells it as cutting “friction,” and the friction it wants gone is the moment you get to say no.