I am for the patirot act, but if you are a US Citizen then you are protected by the Constitution. If not all's fair in love and war.
My stance is if you are not from this country then you zero rights in this country until you have proven yourself to not be a threat. On the other hand, quite simply you could be notified that you were about to be scanned by this device prior to getting onto a flight. Then, it is your choice, two, flying is not a right, but a privelage and a service that you pay for and are subject to the rules of the ticket you purchased. Just like taking a breathalizer is required if asked to do so or you forfeit your license. You entered into that agreement freely and knowingly for the privelage to drive.