As a further aside:
The argument of "Why would they risk having a bad grade?" points to why students arrive in college unprepared to read, and have been doing so for decades.
Not because they are overscheduled. Myself was working three jobs at one point, while taking a full 18 credit load (meaning finding two credit classes to round out the other required four credit classes), during regular semesters, and taking a full load of summer semester classes, to boot. Yet was still reading all the assigned material and plenty of other books every week that were beyond the scope of the syllabi for any of my classes.
This was something myself had been training to do throughout secondary school and primary school before that. Not because getting a good grade depended on it, but because books were how to get to information myself wanted to explore for my own purposes. My reading outside of class had nothing to do with grades, thus my reading in class had nothing to do with grades either.
1/2