We want students to be able to mark certain questions as they are doing them for whatever purpose, for example:
- because they want to go back and check their answer before submitting the quiz.
- because the results will only be released later, and they particularly want to remember to check whether they got this question right.
- because they want to ask their friend or teacher something relating to that question later.
Design document at http://docs.moodle.org/en/Development:Flagging_questions_during_a_quiz_attempt.