I am writing a heavy edit to my own question: Do players know that Wizards don't wear armour?
ShadowKras mentioned the ability to make a knowledge check to determine class features and abilities. If I had known of this, I would have asked a very different question.
But now that I have this information, and am making a large edit to make the question less terrible, should I:
Ask a question that implies I don't know of the feature, and therefore make the answer valid?
Ask a question that includes that knowledge, and therefore makes the actually helpful answer invalid?
Just... abandon the bad question and ask a new one? (This doesn't seem very ethical, but the easiest solution on a purely personal level.)