I read this in a forum from someone in cancun in response to stool testings in Mexican schools
"brice- LOL. Yes. I guess I thought they did that everywhere, this is my first time with a kid! I didn't even think that it was just a Mexican thing. Twice a year, if you don't bring in a clean test you are not allowed to enter the school. Sounds good to me, keep the sickies at home!"