I got one of those new Dunkin Donuts cards as a gift.
The idea is that you go in, order your [weak] cup of coffee, and avoid having to deal with handing over and receiving any money. You just give 'em your card, they swipe it in the machine, and you leave with your order.
That's the idea their ads leave you with, anyway.
What happens when your card doesn't work? (Somehow it got demagnetized before you ever came into possession of it.)
You go in, order your coffee, hand 'em the card, tell them that the card doesn't work and they have to key in the numbers, and they try to swipe it anyway. Then they call the manager over and have a conversation in some non-English language, after which the employee punches in the numbers on the card, and if they manage to punch in the numbers correctly and remember the manager password (Set to '1234#' in every DD I've been to so far) on the first few tries, you leave with your [weak] cup of coffee having only annoyed the growing queue behind you slightly. If not, then you hand 'em the cash because you feel sorry for the sighing people in back of you, and you leave.