Jamba Juice has a deal going where if you get seven of the energy drinks you get the first one and the last one free. Yes, the _first_ one. You walk up and they give you a free drink.
There are seven spots on the card, the first and last are marked free and there are five numbered spots between them. It says in the fine print that it's just one card per customer, but how do they actually intend to enforce that? If i came back next week the person at the register might remember me, or might not. And certainly i could hit every jamba juice in town and get at least one free drink at each one. I don't actually intend to abuse the offer (if i can find a jamba juice near home i might be willing to maintain two cards, but i'm not sure if i can stretch my morals even that far) but i'm sure there are people who have no such qualms.
My brain hurts just trying to understand how they came up with this idea in the first place.