I've never walked through anything but a WTMD. When asked why or why not; I simply state "it is for philosophical reasons".

I'm efficient and prepared when I reach the checkpoint; people can tell I've done this hundreds of times. I've even been complimented by TSA for "being the nicest opt-out they've had".

I then request they pat me down in public - all 6'5" 250lb of me - while i watch them with a distanced and bemused expression. They'll keep doing this until something changes. That's my resistance.