It's a distributed system. You can almost always scan faster than a cashier and you know exactly what quantity and item you intended to buy. Moreover, a cursory

It's a distributed system. You can almost always scan faster than a cashier and you know exactly what quantity and item you intended to buy. Moreover, a cursory (rather than colonoscopy level) scan of "big ticket" items that are commonly stolen is probably more than sufficient to deter most thieves.