Assalamualaykum,
Could guests have a go at the quiz, even if the score isn't recorded in the table?
Also, about the suggestion by sister Taalibah, I think that people should be able to retake the quiz only after e.g. ten days, so that this way the person may know if they really do know the naswer now and that they are not just remembering the answers in parrot fashion from the quiz they took like the day before of something.
Wassalam

