Deirdre Walker, the 24-year police veteran and former Assistant Chief of the Montgomery County, Maryland, Department of Police who wrote up a sharp, professional critique of the TSA's checkpoint procedures, has written a follow-up, showing a huge flaw in the "random" screening process used at the BWI airport:

I asked, "How are people selected for secondary searches?. She replied "It's random."

I asked "Is there a mark on my boarding pass?" She replied, "We used to do that, but we don't do it anymore." She did not know why that practice had been discontinued.

I stated "So you look at people as they are entering the metal detector, you make some type of assessment, and then you select people for secondary searches, right?"

…At this point, I turned to look over my shoulder and observed a Caucasian woman in her late thirties or early forties standing inside the whole-body imager. I called my screener's attention to this and said. "Look over there. There's a woman in the scanner. You all picked me for a search, and then the very next person you select is a woman. Why didn't you pick a white guy? Where are all the white guys?"

She replied, helpfully, "We are understaffed today and we don't have enough male screeners to do pat downs. We are not allowed to do opposite sex pat-downs so we are only selecting women for secondary screening."

By this point, I was seated and she was patting down the bottom of my feet. The secondary search, more thorough than the last search I had been subjected to in Albany, but equally ineffective, was nearing completion. I said "If you are only selecting women, how is that random?"

She said, "You're done. You can collect your belongings, Have a nice day."