In a shift, the Transportation Security Administration plans to replace the walk-through metal detectors at airport checkpoints with whole-body imaging machines — the kind that provide an image of the naked body.The plan now is that all passengers will “go through the whole-body imager instead of the walk-through metal detector,” he said.

In the airports where the whole-body imaging machines are being tested, less than 2 percent of passengers presented with the option of using them are choosing not to, Mr. Kane said.

Consider why:

Not too long ago possession of a cellphone, at least by people in certain socioeconomic classes, was likely to arouse suspicion.

Now it is becoming a social expectation that you carry a phone.

A middle class person without a phone would be viewed as garishly eccentric in a way that arouses suspicion.

Noam Cohen's friend:

Privacy is serious. It is serious the moment the data gets collected, not the moment it is released.