The OPs question made me remember something from my opt out experiences that I never really thought about before. I've always thought it rather absurd that when I opt out of the NoS I'm often directed around - not through - the WTMD. Yet when I am getting the spiel from the groper they ask me if I have any metal implants. Why would that matter if I haven't gone through the WTMD? What difference does it make at that point?