Yes, i know now that is about the account, but if you look at the Bayohne post:
For SE, there are ocean down of North America, i don't think they want to look of countries from South America for the alpha, this is why i think it's a little random.To ensure a broad scope of testing for the Alpha Test, we did accept users with specific types of machines, setups, connection types, ISPs, geographical locations and other configurations that we need to test that may, or may not, meet every requirement on the application. Alpha is an important first step for testing and we need to make sure we have a wide breadth of users testing it.