Other English-speaking countries tend to supply teachers with a little more diplomacy and they usually last longer. Besides, the standards of oral English that some Americans produce indicates that they are in urgent need of some remedial ESL training as well - even after making allowances for the deficiencies in American English.

First off, I don't mean to talk down to anyone. I have no way of knowing the posters' location or familiarity with my region!

I see your point on the first sentence, the following one, I don't think so, unless you meant tourists and not teachers. A native speaker of American English may have speech that's easily recognizable from one of the several (6-9 depending on whose research your reference) major American dialects, but I don't see how it can possibly be an issue with a qualified teacher. Perhaps the difference between written/spoken English is wider here than the UK - I don't know, actually.