I'm not a lawyer and not asking for legal advice, rather I was hoping you would back up your claim with a citation of the relevant law. I think you might have

I'm not a lawyer and not asking for legal advice, rather I was hoping you would back up your claim with a citation of the relevant law. I think you might have an overly broad conception of the duties of a teacher towards students. They should protect them from harm, so laying an actual trap (or just not warning about a potential danger) so that a student gets hurt would be in violation of the teacher's duty. But giving your students a test to make sure they're actually studying is such a common (and common-sense) expression of distrust that I'd be surprised if it were illegal to not expect good faith from their students. Relevant: §2 LehrErzVDBest https://www.gesetze-im-internet.de/lehrerzvdbest_1/DDNR000190966.html#DDNR000190966BJNG000100307 https://www.gesetze-im-internet.de/lehrerzvdbest_1/DDNR00019... (Former GDR law that was kept in force after reunification. Not sure whether the part about not doing damage to the socialist society is still part of current law.)