College is different from high school; the counselors are much more hands-off, leaving it to the students to be self-disciplined.
Although some professors take attendance, students can have someone else call out 'present' for them, or if they can manage to pass the final assessment without failing, or simply don't care, they can choose not to attend classes.
Skipping classes is a common occurrence for college students, but ultimately, it's not a good practice.
Liu Yu's shout was deliberate, aimed at tarnishing Lin Baici's reputation among his peers by casting a stain on his image.
