All this "burquini in pool thing" never had been a topic ... until some years ago a female Muslim pupil didn't want to take part in school swimming because of boys were there, too.
Want up through all the courts. Then the Federal Constitutional Court decided that she had to take part. Because she could swim with a burqini.
Some municipalities changed the wording of the regulations afterwards (Konstanz [Constance] was most noted in the media.) Others either didn't have a explicite wording describing the swimwear or didn't have problems or just didn't bother.
Here, no-one bothered before as well. And only because those four ladies wrote a complaint ....