Body scanning will be mandatory in the Los Angeles metro, but dishonest officials want to have it both ways: "The screening process is voluntary, Wiggins said, but customers who choose not be screened won't be able to ride on the subway."

If the scanners don't recognize and identify individuals, and if they don't use dangerous radiation such as X-rays, maybe they don't do much harm. But I presume someone will physically search passengers when the scanner "finds something". So the next question will be how many false positives there are, and what happens to those people.