Decades ago, my father would have some fun with the receipt checkers at Costco. After a shopping trip, we’d commonly have lunch at the cafe in Costco. When leaving the store, he’d hand the receipt checker the receipt for lunch rather than the receipt for the items bought. More than half the time, the checker would just swipe the receipt with a highlighter (their way of marking it “checked”) without noticing that it was the wrong receipt. So ya, it’s complete security theater. Anyone with a modicum of thought can figure ways around it, and it only accomplishes inconveniencing the people who aren’t trying to get away with anything.