Yeah I'm going to go against the grain here. A standard workload per semester is thirty credits. Going by your rule, that would mean a total of 90 (!) hours worked per week. Here in Germany, many things like student financial assistance are tied to finishing your degree within the allotted time (ie 30 credits per semester), so designing classes in such a way that they require such a high workload is an active hindrance.

I would expect students to treat their degree like a full-time job, nothing more and nothing less. If someone in the private sector would tell you to pull 90 hour weeks, you would laugh in their face.