Several years ago I worked at SportMart, a sporting goods chain. I worked behind the service counter, where people would bring their returns and exchanges. One day, a woman came in carrying a pair of roller blades she had purchased the week before. She told me that one of the blades was the wrong size - there was one Regular and one Large, and she wanted two Larges. She proved this by pointing to the R and L imprinted on the padding on the inside of each of the skates. I carefully explained to her that the skates were the same size, and the R and L stood for Right and Left. She left without comment.
(From the "Rest" of RHF)