My sons go to a private Japanese school (in Japan). They are required to take English classes, and the fact that they are fluent in English is not taken into consideration; they take the regular class with the other students. This leads to some funny and many frustrating moments for all of us, for example when my sons are marked incorrect for not using exactly the same wording provided by a teacher, although they are nonetheless equally correct. It drives them crazy, having to memorize the one and only way they can respond in order to do well in class--a kind of unlearning, almost.
But there are the funny moments as well. For example, this week my son in junior high is learning about the passive voice. He brought home a worksheet with the title "Let's Speak Passively!"