The German school system doesn't take kindly to this, AFAIK. Maybe if we temporarily gave up residency, but as far as I know, the equivalent of CPS would have some questions.
Yes. A friend was homeschooling her kids in the US, and then her husband got an assignment in Germany for about a year. She took the kids and joined her husband in Germany for a few months. The rules were all different, and much stricter in Germany. I remember she was thinking of trying to continue to home school there, and keep her kids inside during school hours, and try to slide under the radar. I don't remember if she got away with it or not.
If I may say so, your friend isn't the brightest candle on the cake if she didn't research the rules before and then tried to dodge them. I bet she would have cried foul murder if CPS came to her house and threatened to take away her kids...
I double checked, and my friend successfully got away with homeschooling her kids in Germany. This was over five years ago. She thinks that maybe because she's American, they didn't follow up as much as they would have with a German citizen. She also told me today that she was there for almost a year, not a few months.