A common practice with some groups of students is to catalog exams/questions used by instructors so that future students can refer to them when studying. Often instructors will use question banks (item banks) to help combat this so that each student only gets a subset of available questions. However, with enough students printing out the completed exam questions eventually they will get them all in their collection.
It would be helpful if there was a setting which allowed students to ONLY view questions they got wrong after taking a quiz. So at the end of a 50 question Quiz they wouldn't see all the questions, only the 3 or 5 that they missed. This provides good learning feedback to know what they got wrong, but doesn't open the entire test up to be copied and banked into their files for future students to refer to when studying. This will help preserve the integrity of the question bank being used by an instructor and not require the need to re-write and replace questions nearly as often.