if it was like math 2z03 that was so packed that we would rush for seats, not fair for those students to take up seats.

If its empty why not

I see people do this all the time unofficially. I would love to sit in on some history classes cause I enjoy learning about it but don't want to write essays and exams and its irrelevant to my studies. I saw lots of people auditing relig 1bo6 out of curiosity but that class had like 600 people and no one cared. Unofficially auditing a class with 20 people in it just doesn't seem right though there was one auditor in class of 15 I just did.

right now I am considering unofficially auditing a math class before I take it for real cause I am terrible at math and it might be the edge I need. If there is room why not? Mac gets enough of my money as it is so I'm not going to feel bad about learning for free. As long as your not disturbing anyone I don't think its a big deal.

Way I see it is that $500/course fee pays for the exams (there was a similar system back when I did IB in HS). But I don't think is very polite to audit a class with like 20 people, or one that is so popular even the registered students have trouble finding seats.