Re: They cheated on the exam and it's just not fair... should I tell prof?
In fact, after a test, you can make an appointment to see your answers to know what you did wrong and right (as preperation for resits or just for your own evaluation). They do not allow to copy the questions literally, but you are allowed to note down keywords.
That proves that if you know the questions by heart and you remember them, then you can discuss them with your fellow students.
Not that it matters much, because the questions at the resit will not be exact the same.