Apart from countries where English is taught as a second language only to immigrants and indigenous peoples (e.g. Australia), where is American English not chosen as the dialect taught when teaching English as a second language?
I have a suspicion that in former British colonies like India, British English would be taught instead.
There is generally no single policy across different countries as to what English is taught across the board. Countries in Europe and Asia default to British English - the most popular textbooks (Headway, Matters, etc.) are based on British English. I imagine this may be different in Latin American countries - but I have no data on this.
A very common scenario around the world is American teachers teaching using British English materials. Students are also exposed to more American English through global media. Many teachers are only tangentially aware of the range of differences between the two Englishes leading to frequent confusion.
I was taught BrE at school in the Czech Republic. I wouldn't be surprised if it was more common in Europe, simply because of geographical closeness and history.
I do not know what kind of English we were taught in Russia. It had American-style vowels, but no rotacism. I also think the spelling was British-like, but this could depend on a textbook (official and Soviet-style textbooks would use British rules definitely).
So people who went to British-speaking countries said "we were fooled in schools, they pronounce the vowels more like they are spelt than we were taught".
