I enjoyed the ending where the participants then turned things around...
...and introduced the hamburger makers to their own culture.
As for the taste tests taking place within 15 minutes of a McDonalds or Burger King, I had the impression that they brought the people who lived in remote areas into the major city of their country to do the test.
I have no problem thinking that there are people who don't know what McDonalds is. Even where I live, northern Quebec, there are people who don't know what a Wendy's is, or a Jack in the Box, or an In-N-Out Burger, or a Taco Bell, or a Chili's, or an Outback Steakhouse, or, yes, even a Starbucks. I find myself explaining these concepts pretty frequently.