One time, while going into Panama, the border agent wrote a couple words on a sheet of paper and asked me to pronounce them: ship, sheep. Thinking this was some kind of shibboleth, I complied. She then wrote a couple more, I think they were chair and share, again I complied. Finally she wrote another pair, I don't remember what exactly, but I was getting very worried that this was some kind of bizarre profiling by accent and I was about to find myself in a Panamanian detention center.

She looked up and laughed, and in very broken English explained she was trying to use the accents of incoming Americans to improve her accent to help in her job when dealing with English speaking foreigners.