Kit was in the 2nd or 3rd class of primary school when he first disagreed with his teacher. It was a biology class, or rather general studies (Sachunterricht) at that age. My son has always been tremendously interested in biology, among other things, so he constantly researched, learned, and excavated some new information. When his teacher claimed something about bats, which was according to the school books, Kit respectfully disagreed and corrected her. Her reaction was great.
Kit's class also learned that authority figures can sometimes be wrong.
Some months later, or maybe another year, there was a similar situation again. Luckily, Kit always felt free to voice his objections, in a calm and objective manner and, luckily, the teachers were cool about it. They didn't let their ego get in the way of education.
There can be no shutting up when it comes to learning, there is no room for censorship. Not if you really want to find out things.