When your livelihood requires that you fly, it's kind of bogus to claim that you are flying voluntarily. On that same argument, you are not "required" to work in a mine, so we really shouldn't force safety standards on mine operators. They can just go work somewhere else, right? Most of us believe that safety standards are a Good Thing overall, although I know some people disagree. Those people generally have not been forced by circumstance to work jobs that really need OSHA standards, so I don't have a lot of patience for that.
The concept that just because you do something of your own volition, you sign away all of your rights, is ridiculous. It's not unreasonable to demand that the TSA only take those steps that are demonstrably effective, and don't cross the line of being gross violations of our rights. It's not unreasonable to expect them to do their jobs better, and not resort to security theater.
When the TSA figures out how to scan ALL of the luggage, not just some of it, without valuables "disappearing", when they take some lessons from countries that have been dealing with actual threats for years, when they are consistent from airport to airport in the SAME COUNTRY, get back to me. Until then, stop poking screaming 6 year olds, stop lying about what your scanners can and cannot do ... just stop already.