Isn't that the purpose of International school like JIS/BIS and a like, to provide an education for foreigners who reside in certain country where school/education are not in the same standard as the education back home? Certainly, Int'l school was not made to provide education for local citizen.
And for mix marriage family, like me, it is fall into our choice where to put our children. I have decided from the beginning that my children will not receive their education in Indonesia, therefore their path would be international school when we are not in husband's home country. If in the future, I see that having Indonesian education gives more advantage, they will then need to have National Exam. In fact, we have changed our mind once, I put them in British School thinking that they will have their continuing education in england, but after getting more educated myself, I've seen that opportunities for those graduated from USA is more than those graduated from UK. I am seeing it with my asian eyes of course.. You see, even with international school, all again depend on your voice. As a mixed marriage producing dual citizen children, if you decide to raise your kids under their Indonesian citizen, they should receive Indonesian education as it is not only teach basic knowledge like math, english etc but also to have the essence of Indonesian.