I occasionally work at gamestop (2nd job, mainly for the discount)
may have accidentally hit the button. after scanning the barcode the POS throws a bunch of probts up, things like: Of age to buy M rated games? Purchase Warranty? and a few others I can't think of at the moment. So it is possible he just hit the wrong button and added it. Hell, most of the time I don't even ask people if they want the warranty, 99% of people don't want it.