It’s many years ago and pilot fish is working at a smallish consulting firm with informal purchasing procedures: Someone just goes to the local computer store and buys any needed equipment or software. There’s one employee who always seems to jump at the chance to do it, and fish wonders why, other than the chance to get out of the office for a while.
So he asks, and he gets an honest answer: It pays. The eager shopper gets cash back when he uses his credit card, and all those office purchases are adding nicely to his monthly rebates. It works well for him because the company is reimbursing him before he gets his monthly statement.
And it works for a long time, but eventually the company gives him a corporate credit card for making any office purchases.