And the attendance control varied among all the professors. I remember that the lecturer for thermodynamics had this system: you write your sequential number and last name on a piece of paper, and then he counts the people in the auditorium and compares it with the number of people who signed up, and if it doesn't match, he does a roll call. But he treated us like idiots and never counted the number of entries on the sheet, only looking at the last number... which, of course, we took advantage of, writing several people under the same number in the middle of the list.
Added 10 minutes later
MasteR, organize a Mafia game; it will be fun!