I've had it done in a couple of places. At one time, a TSA screener somewhere (may have been IAD, or BWI) was checking IDs when entering the WTMD. He looked at my passport and then tossed it - like a softball pitch - into the grey bin headed into the x-ray. I came a bit unglued at him over that, pointedly asking him if he treated his family's stuff that way, and asking him what would happen if the passport were lost. He was at a loss for words.... nor could he explain why he'd let folks take their DLs through the WTMD, but not a passport. No respect for passengers or their things.