I used to opt out due to radiation and privacy concerns when airports were using the backscatter scanners.
After US airports switched to millimeter wave scanners, I no longer opt out.
My understanding is that the new scanners emit far less radiation, and no TSA agent operator is viewing naked images.
The software presents a stylized body silhouette on a monitor that you and the TSA agent both view when you exit the scanner.
If my understanding is correct, then isn't this a reasonable approach?