The answer is: Feldman’s payment system was largely successful.
In the excerpt from "Levitt and Dubner’s Freakonomics," the speaker reinforces Feldman's affirmation that people are mostly honest because he used to distribute the bagels in the morning first, and he collected the money after the customers had taken their bagels by midday. Singularly, the customers actually paid him and he earned more than he did as a research analyst.