I can imagine that just fine and it's horrible. I love in a country with a fuck ton of Muslim immigrants and I'm sure a lot of their children would prefer not to have to cover their hair (that's what we're talking about, not a burka as you describe it).
Yes it's a powerful tool to keep kids under the influence of their parents religion. But taking away the symbols of that religion won't make the kids atheist or magically take them out of the influence of their families. If you think that parents who enforce the strict rules of their religion because the kid can't wear certain clothing at school, you are Truely delusional. Best case the lod doesn't wear it in school, but still has to do so every other minute in their life. Worst case the parents pull their kids out of school, because the school threatens their influence. A lot of those kids are going to end up home schooled by their radical families or simply go to a private school, where such rules don't exist. Neither is going to help the kid.
As so one who gre up in Bremen: How dare you.