I'm actually really glad that schools are sending the message "don't use Wikipedia as a trusted source". Students and parents naturally being contrarians will ... use Wikipedia, or learn to read primary sources and re-cite them, which is a step towards primary source research and a step in the direction of critical media consumption.

If students and teachers happen to notice that the Wikipedia consensus is close to reality … that's a great side effect. Teaching them that the raw consensus of most Internet users is generally trustworthy is a pro-social exercise (even if you do it in a sneaky way by triggering students' rebellious instincts). And teaching them that their teachers are misguided in the way they talk about Wikipedia is, arguably, also a good critical-thinking exercise.

An alternate exercise that schools or parents could do is to have their kid try to introduce a false fact into Wikipedia and see how long it lasts or whether it can enter reality via citogenesis. It's better that kids are not introduced to this concept. I'm glad that it's not done.