We'll document it once we have more than two hours of data from the test drive to see if it works, if we're keeping it, what we're changing (if any), etc: the FAQ is for permanent or very long term information, not for "we're trying this thing, it may work, it may not, we may change it back". But I will note that the reason we chose those particular countries is because the amount of legitimate usage from them is very, very low, and the vast majority of new account creation from them is overwhelmingly spam.