This is also why modern nuclear power plant design seem so safe. And then something they didn't factor in shows up, or someone takes a sloppy shortcut in building or regulations that wasn't accounted for and suddenly there's no way to undue the damage (and no way to stop the failure).
If they won't let TSA agents wear dosimeters, well then you'd have to be a moronic zombie to become a TSA agent and work around these machines. And that's predictably who is left working there. But hey you can sue for lack of benefits when you are dying of cancer, only to be told on your deathbed that you fall within the range of people who get cancer anyway, couldn't be the machine.
I'd say "stop flying" but of course these machines are now in portable versions in vans and they can just drive down a street and expose everyone to it, opt-in or not (this really exists, it's not tinfoil hat paranoia http://google.com/search?q=backscatter+vans ).