When I attended school in the late Middle Ages, I never wondered whether I was taught British or American English. I suppose I was taught both: differences in pronunciation, vocabulary and grammar. I find it strange that anyone would like to confine his knowledge of the language to just one variety. Why on earth? And how could that be possible?
I have seen him is both British and American! I don't know how it could be possible to learn just one variety as they are so similar, after all. The dialectal differences in Britain are far greater than the differences between British and American English, as I have said before in some other thread.
Brits understand Americans even if they have never been taught American English, and vice versa. If a Finnish teacher of English has spent a lot of time in England or the US, he may be more familiar with one variety and may thus want to emulate British or American pronunciation in his teaching. The students can't help hearing both because all the texts in the books that are used are recorded on CDs by native speakers, who include Brits, Americans, Canadians, Australians and even the occasional Indian. All these nationalities are employed in nationwide listening comprehension tests as well.
When a Finn is enrolled in a university, few of the books on the syllabus are in Finnish unless he studies Finnish Philology or Finnish History or something similar. If he studies social sciences, biology, medicine etc. the majority of the books are in English. In some cases he may be able to choose a book in another language also, usually Swedish, German or French. As a rule, it is safe to say that university studies are not possible if you are unable to understand scientific books written in English. These books may be written by Britons, Americans, Finns, Germans, Spaniards or people representing other nationalities because English is the leading language of science and no university can function properly without English. Some of the visiting lecturers and professors don't speak a word of Finnish!
It seems utterly trivial and futile to me to try to concentrate on just British or American English when one just can't manage with only one variety and the differences are so small.
Cheers
CB