I remember hearing a saying years ago about how computers are only as smart as the person using them. We rely on those POS systems for everything we do. We use them at most stores and restaurants we shop at. Who is to say they are on the money? I check my receipt every time I go shopping. I even started to use the self checkout lines where you can scan your own groceries or goods. That way I can check the price as I scan them instead of watching a person do it at Mach 9.