Good Lord, that Tesco thing is sick.
I am hardly an expert on burqa-wearin', but I would hazard that the consequences vary widely. There are certainly totalitarian regimes, like the Taliban, in which not wearing a burka (or, for men, not wearing a beard) is enough to get you killed. There are certainly less extreme places where nonetheless wearing "only" a headscarf is grounds for social ostracism and harassment (but then, exposing more flesh than the local standard also produces social ostracism and harassment in American, and probably Swiss, high schools).
Among the 100 women or so in Switzerland who wear burqas, it's conceivable that some have abusive husbands who would beat them or kill them, or not let them leave the house, if they refused to wear the burqa. There are undoubtedly vastly more white Swiss women with abusive husbands who are going to beat them for refusing to get boob jobs, or (contrariwise) for dressing too "slutty".
There may also be, I can well imagine, among those 100 burqa-wearers, some whose husbands are embarrassed and anxious about all the harassment from Swiss people that they are attracting, and who would love their stubborn wives to tone it down a little, and whose wives say "the hell with that, you loser, I am proud of who I am and I'm damned if I'm going to start parading around like those Western bimbos just because you're scared."
Recently I read a book about Bosnian Moslem teenagers growing up in Switzerland, and one girl was talking about wearing a headscarf. In her family, she said, no one would make you wear a headscarf if you didn't want to; indeed, you decided yourself when you were ready. But that decision meant choosing to be a grown up woman, and a grown up woman of a particular sort: it meant choosing to be like your mom, choosing a set of values which she, at least, associated with integrity, clarity, and safety. She chose to wear a headscarf for the same reason she chose not to get drunk and laid at the parties she tagged along with her Western friends to; and the headscarf helped reinforce those decisions, and probably to warn off the date rapists. And you could tell how tired she was of the question "do your parents make you wear it?"