It used to happen only at smaller airports that didn't have the capacity to handle extra lines. But lately, I've had it happen at bit airports (like ATL), so I'm not really sure.
The answer to your (implicit?) question is that it doesn't work. The staff take the card from you at the start of the process, and once your bag is in the machine, they have no idea if it's yours. So far, every time this has happened, I"ve been singled out for additional security.
The answer to your (implicit?) question is that it doesn't work. The staff take the card from you at the start of the process, and once your bag is in the machine, they have no idea if it's yours. So far, every time this has happened, I"ve been singled out for additional security.