I guess this turns out to be another urban legend, but you reminded me of the story:I remember in the late '70's working as a summer bike mechanic at a Toys R Us. Their business model back then was to sell diapers at cost. It was smart because it got people in the door and that is half the battle. It takes a strong willed person to walk out of there with only diapers.
“Some of the ways Wal-Mart managers found to exploit their findings are legendary. One such legend is the story, “diapers and beer”. Wal-Mart discovered through data mining that the sales of diapers and beer were correlated on Friday nights. It determined that the correlation was based on working men who had been asked to pick up diapers on their way home from work. On Fridays the men figured they deserved a six-pack of beer for their trouble; hence the connection between beer and diapers. By moving these two items closer together, Wal-Mart reportedly saw the sales of both items increase geometrically.”