First, let's talk about luck. Universities don't call the roll every class. If the teacher happens to call the roll in this class when you are absent from class, you will win the lottery, and you will be absent from class once.
Second, look at the way teachers do things. Some teachers call the roll more often, some teachers call the roll less often, and sometimes teachers call the roll when too few people come to class. Absence from class beyond the teacher's bottom line will be deducted or suspended directly.
Third, the academic system. Theoretically, every school does not allow students to be absent from class. In the event of truancy, different schools will have different punishments. You can check the school regulations yourself.