Square Handheld is a compact, portable point-of-sale (POS) device built to serve the ... an integrated barcode scanner, and a 16-megapixel camera. Square Handheld supports tap and dip payments ...

If they have one of these scanners, theoretically they would be able to steal credit card data if they're within close proximity, and you wouldn't even know it. But they've got to be close — usually ...