A discount for signing today

At the till of a large shop in a Kuwait City mall, a young woman is offered a generous discount on her basket if she opens a store card before she pays.

She is an adult. She can read. Nobody is forcing her. The usual view is that this settles it: people know what they want, they choose, and they live with what follows. It is not the cashier's place to tell her how to manage her money.

For a lot of decisions that view is right. Which sandwich, which colour, which film tonight. The cost is small, the result arrives quickly, and if we get it wrong we learn by Thursday.

The store card is a different sort of choice. The saving is today and visible. The cost is spread over years and lives in terms she will not read in full. The person suggesting it is rewarded when she says yes. The card makes the next purchase easier, and the one after that. And she is deciding in two minutes, at a till, with a queue behind her.

That is how most of us decide. Not with careful research, but with whatever is in front of us: the excitement, the word discount, what friends do, how it feels to say no in front of strangers. Nobody runs the numbers on every offer, and we should not pretend that we do.

The textbook picture of a market assumes a calm buyer with complete information. Real buyers are busy, hopeful and easily steered, and some sellers have learned exactly where to push.

None of this means taking choices away from people. It means the people designing the offer carry a responsibility the buyer cannot. When thousands of quick decisions add up, it is fair to ask whether the offer was built to be understood, or built to be signed.