Unfair advantage?

This is another interesting incident during the seventies. There was a student in the M.Sc.Tech class who was very intelligent and innovative and equally irregular and lazy. He almost always wrote what is necessary for a pass in the exams... Not more, not less.. Well, just a little bit more to guard against ant misfortune. Sometimes that little extra got him more marks and there were occasions when he stood first in the class ,specially when the paper was difficult and others could not get many marks. This happened more times in my subject, may be because he was more interested in the subject or may be because I admire innovative answers.
One day I got an anonymous letter from one of the students claiming that this boy was getting early information about the question paper. I was more amused than annoyed since my papers were always set minutes before the test and even I did not know beforehand, I AM very intuitive by nature.
So next time the test was due, I announced in the class that I got such a letter and I know who wrote it( I did, after all I usually collect info about ALL students) I am not bothered. Anyway since there is such a feeling, I do not want anyone to think somebody got a unfair advantage and I am giving all of them the advantage by disclosing the paper on a friday and holding the test on monday.
I am sure you can imagine what happened in that test.