First of all, Fudan Academic Affairs Office has a curriculum, which is open for download.

Secondly, about skipping classes. There is a sticker at the bottom of each teaching building, which says what classes each classroom should take (in fact, it is also indicated on the class schedule).

Then, the average teacher won't notice that there are outsiders, unless there are some small classes, such as English class, physical education class.

Finally, I admire the spirit of my classmates.