The recent reports that the TSA is planning even more intrusive pat-downs raises an important question — what are the limits on on the intrusiveness of TSA procedures?
https://www.bloomberg.com/news/articles/2017-03-03/u-s-airport-pat-downs-are-about-to-get-more-invasive
Unfortunately, since the TSA has NEVER attempted a rational cost-benefit analysis of their procedures, it is pretty difficult to see what those limits would be. It is hard to believe, but the TSA does not attempt a formal evaluation of the costs and benefits of their procedures before implementing them. They didn’t do so when they asked people to start taking off their shoes and they didn’t do so when they installed full body scanners. (Indeed, they illegally resisted court orders to perform formal rule-making regarding those scanners for several years.)
What appears to go on with TSA decision making is a sort of off the cuff guesstimate that a procedure might reduce risk. And normally reducing risk of a terrorist attack, even by a minuscule amount, is assumed to be worth nearly any cost. But of course, without trying to actually quantify the costs of the procedure and the level of risk mitigation it is impossible to know whether such a procedure actually improves safety for the traveling public overall or is worth the cost.
This lack of precision makes TSA decision making essentially subjective and thus subject to all sorts of biases, such as the desire to favor a particular contractor with a large contract award because they are your former colleagues or have entertained you nicely.