Let me clarify.

At the WTMD, you have the option of removing your shoes, if they meet the screening criteria. Shoes that meet the screening criteria can be screened either by x-ray or ETD sampling.

However....

if your shoes alarm the WTMD on your first pass, the screener can explain that your shoes caused the alarm. (There's an indicator panel on the screener's side of the WTMD that lights up in the area of the alarm. It's not 100% accurate because sometimes a pack of cigarettes stored inside someone's socks or a cell phone inside a lower pocket such as one of those cargo shorts that are popular today will also indicate an alarm in the same area as the shoes.) You have the option of either removing the shoes (since you now KNOW that they alarmed the WTMD) or undergoing secondary screening.

At secondary screening, if your shoes alarm the hand wand, those shoes have to be x-rayed, and your feet have to be hand-wanded without your shoes on (if you are sockless, then all that is required is a visual...unless you're wearing very saggy trousers that cover most or part of the foot...the screener would then be screening the top of the foot and ankle). You may request that screening not resume until your shoes are returned. I have had some disagreements with my own peers on this point; they believe that someone could theoretically slip a prohibited item back into a shoe if permitted to put the shoes back on before being completely screened. As a master of diversion and concealment in my former profession, I find this theory laughable. The SOP does not specifically address this point. I think it's good customer service as well as common sense to allow a person to put his or her shoes back on after the feet have been either hand-wanded or visually inspected before continuing to screen the rest of the body---if the passenger so requests. Most people, about 99% of them, just want to get it over and done with and aren't interested in putting their shoes back on until the hand-wanding is complete.

If your shoes did NOT alarm the WTMD but you are referred to secondary screening because they met the criteria, then all that is needed is an ETD sampling of your shoes. However, there's a catch to it: you cannot have any contact with anyone who DID alarm the WTMD or else you'll have to undergo the Full Monty as well. We try to segregate passengers who alarmed from those who did not; but our goal is to immediately respond to those who didn't alarm because all that's required is a simple ETD sampling of the shoes.

If you're wearing medical shoes or cannot remove your shoes for medical reasons, the SOP allows us an alternative screening method.

The issue is, has been and will always be clearly understanding the SOP. It disappoints me whenever I read that there are still screeners out there who don't know the SOP. I quiz my screeners daily with a "question of the day" (followed by a "Chuck Norris fact" just to start the day off on a humorous note).

Hope this clarifies any confusion on shoes.