After checking out at a U.S. supermarket, someone will briefly verify your receipt and the items before you leave. Many people’s first reaction might be, “Is it meant to protect against me?” But there’s actually another logic that’s easy to overlook here: it’s not only checking whether you have any issues, but also helping to check whether you were charged too much. In other words, this action is both a system mechanism to prevent missed scans, duplicate billing, and reduce shrinkage—and also a form of protection for consumers. It doesn’t start from “you might be a bad person,” but rather from “in high-frequency, complex transactions, errors are possible,” so it uses a very low-cost check to fix potential mistakes that could harm either the merchant or the customer before they exit the system. Seen from another angle, this kind of verification isn’t a lack of trust in people—it’s a way of managing the imperfection inherent in transactions themselves.