I bought stamps at the Post office today and saw that they have new terminals for swiping credit cards. It was this one, or one just like it.
Perhaps because I was looking at the pen, but I tried to swipe the card in the slot just under the pen. But that’s not where the card goes, that’s just a space between two parts of the device. The card goes in the space just above the keypad (which wasn’t lit up when I used it).
The funny thing is that the clerk said that I wasn’t the first person who did that! Maybe a little usability testing would have helped.
Update (7 Aug 2014)
When I bought stamps today, I noticed that the slot at the top of the machine was covered with tape. The clerk said they had to do it because so many people tried swiping their cards there.