Yup, they do it. It's random, though. My wife (who is Japanese) was picked once and I was not. Very odd. They made her take off her shoes, show the contents of her purse, etc. while I just stood there in my DM boots with my heavy messenger bag.

No idea what criteria they use to select flights or people for screening. Sometimes they don't do it at all, but they have on three or four of my flights and my wife was picked out that one time.