Alexander and Christine Clement, a couple of sixty-somethings from Long Island, came up with what they assumed was a foolproof scheme to get all the free Jell-O pudding they could get their hands on. They'd purchase boxes of the dried mix, take them home, make the Jell-O, then — ostensibly while the dessert was setting — fill up the empty boxes with sand and return them to the store for a full refund. Then they'd go home and eat their fill of pistachio and butterscotch pudding, all the while congratulating themselves for having saved a total of $1.40 with their cleverness. For a while, the scheme worked like a charm.
No one thought there was anything funny about old people returning packets of Jell-O to the supermarket multiple times. Old people return everything! And no one noticed that the packets were full of sand, because no one ever buys those flavors, or really, Jell-O at all. But then someone did. Per the Post:
The scheme fell apart after a customer who bought one of the resealed boxes complained. Police traced the boxes back to the Clements.
In retrospect, they should have tried it with Metamucil. No one would ever have known the difference.