If you instead throw them curve balls all the time such that they reward themselves for solving the tricky puzzle or feel slightly ashamed for blurting out a phrase which doesn't connect to reality, they will learn to think. Maybe.

The tricky part here is not to shame them too much; otherwise, they might stop answering questions at all.

It's important to encourage trying things, at the same time as you try to discourage trying random, haphazard phrases. Sometimes it might be hard to tell the difference.