TWAforever:
Exactly. My wife and I refuse to take off our shoes and unless they hit the hidden button to set off the detector, we never get the secondary search because we never set off the detector.
You are correct that it is only a "suggestion" that you take off your shoes, not mandatory. I suspect it is because they are lazy and don't want to spend the time to have to reprocess or secondary search ma and pa Kettle who walk thru the detector with all kinds of metal in their shoes.