I disagree with this statement. Every student knows which courses are the easy ones. Obviously, "easy" is relative, but we all knew which courses were easiest at Duke, right? Everyone I knew did, anyway. We called them "crip" courses.
Of course, knowing which courses are easy doesn't mean everybody chooses them. It doesn't appear as if the students in this UNC situation were encouraged to branch out or challenge themselves intellectually. But that's different from encouraging them to sign up for it.