As per your second point, maybe we could actually go like this: every new invasive TSA procedure would be A/B tested on similar flights (same departure and destination, comparable times, same price).

Do people want to be strip searched? Well, let's find out. You can take flight A where nobody is strip searched, or flight B where everyone is (all other existing security measures unchanged).

If nobody (but me) is willing to take flight A, we have the answer we're looking for.

My point was that everyone assumes that nobody will take flight A, but in fact we don't really know.