[336f5]

>> Why they do this, I have no idea.

> I'm not saying there aren't any valid reasons for doing it.

> I'm just saying the there's a "meta-lesson" there that has to be corrected.

And I'm saying that your meta-lesson is not a good idea as it will tend to teach underconfidence. The real world does not always let you off with a "I don't know"; you may not know to some high degree of certainty whether a cancer treatment is a good idea, but nevertheless you must decide whether or not to do it.