"Opting out" means everything takes longer & they physically molest you every time, so given that the cost & personal violations increase, there is no real way to opt out. And there is like a 110% chance that face tracking is still being used via security cameras anyway so you are just being doubly punished for some false sense of "I'm not in their database." You walk through an airport, & probably a Bank of America, or any other politically connected corp monstrosity, you're being IDed & tracked.
Discussion
I think it is important to do what you can to protect different aspects of your privacy, but it's also important to be realistic. If you are using a stock apple or andriod phone with facial recognition to unlock your phone, the idea that you can achieve any sort of facial recognition privacy at this point is probably retarded. Cameras are everywhere. You are being recorded by your own devices & by other people's cameras basically everywhere you go.
Reducing the spyware in your own home is far more important to focus on than what happens in an airport or some other place that you really can't control.
Opting out of face scans isn’t invasive at all and doesn’t take any longer. They just scan your ticket and that’s it. I mentioned it because most people don’t even know it’s their right to opt-out.