Happened to my wife, who likes to shop at discount stores in NY like the former "Filene's Basement" (RIP). My grandmother bought my wife a sweater from Henri Bendel (and my Grandmother buys a LOT of stuff at that store) and when my wife went to exchange it for a smaller size she happened to throw it into a Filene's bag when she left the house. The saleslady accused her of trying to buy a sweater at Filene's and return it to Henri Bendel. My wife insisted she look up my Grandmother's name in the computer and saw in fact that she not only bought that sweater there, but also is a good customer. The salesgirl was very apologetic after that!