All students should fully attend class. By attend, I do not mean solely being physically present but fully in cognitive attendance.
Attendance means paying attention to the class lecture and discussion, taking notes, offering details from the pre-class readings, and carefully defending each argument. Students who passive sit through class sessions are not attending class, they are filling a seat. Attending requires paying attention to the material being discussed and participating in the discussion.
I am dismayed by the number of students who are willing to discount the value of pre-class preparation. Rather than taking a few hours to carefully review the assigned readings on the evening before class and taking detailed notes while reading, these students, can they even be called students?, lose the advantage of careful preparation before the class discussion and may not recognize and comprehend the nuances of the details presented during the class lecture and discussion.
Attending class requires pre-class preparation, as well as physical and cognitive activity during the class period.
In online classes, attendance is similar to onground classes; however, the participation is written, rather than oral. The type and amount of pre-class preparation is the same, regardless of modality.