Hmmm... I could see how an ascetic-ish (er, that's the wrong word, but you know) sect might want to move from, say, the United States to a country of less privilege like Mexico. Though we never hear about them, I suppose there might be a lot of missionary activity happening for that reason. Though I still suspect the UD posting was meant as a joke. ;-)
I thought it was pure joke when I first read it, but maybe not. I spent some time in Central and South America in the early nineties, and was surprised to come across communities of Mennonites in more than one country (to wit). Maybe there are similarly far-flung groups of Amish.