Im a runner,so I had to post.That being said,I have ran a ton of races and I wouldnt even do a 5K with that,haha!!!
I think you were meant to say "people from US, Liberia and Burma". IIRC those are the only countries that don't use metric system.
Not sure why(Even as a runner myself) but runners have a history of dressing up and running in various costumes and outfits.In any foot race you're liable to see someone dressed in something weird.