Smart cards are loaded with a chip containing all of your personal information which is read instantly by a scanner. It's supposed to speed up transactions, and some people already have these new cards and don't know it.
It's not really new technology, but this new use poses a new danger. Using a hand held scanner, a crook can actually lift your personal information off your cards, even when the cards are tucked away in your wallet or purse.
"In a crowded stadium or something, I could just be walking past someone," said technology expert Walt Augustinoquicz. "They'd never know that I just scanned their data and I'd go home and have hundreds of credit card stripe information on my laptop."