"And this is why we have the system that we do. In a world of telepathic humans, one human who can hide thoughts would have an enormous advantage. Let the others think they are eating their fair share of the elk, but sneak out and take some strips of meat off the salt rack when no one is looking. And then insinuate to Sue that you think Juan did it. Enjoy the extra resources for more calorie-gathering and mate-hunting, and also enjoy the fact that Sue is indebted to you and thinks Juan is a crook.

This is all terrible behavior, but after several generations, there will be many more copies of this module than Juan’s honesty module."

-- from the article.