With the L3/Leidos MMW units, it's been much easier to find ways to avoid having to opt out and just go through the WTMD due to those requiring the passenger raise their arms and submit... I've never been through one of the "scanners" and haven't had to opt out since 2012, so it certainly makes trips more pleasant. As more of the Rohde and Schwarz devices appear, it will require more opting out.