So I live in Andalucía in a small town where there's lots of "world schoolers". Essentially, they have setup their own learning programs and do whatever they want. Maybe its because they're foreigners but they've never been bothered by the police even though they're quite public about it. They've told me that in Spain homeschooling is not illegal, rather alegal.

I suppose once you're in the system though it's difficult to extricate your children from it.