The use case is the following:
I just had a lecturer complaining: "Assignment and Quiz score tables are sorted differently. In one Albert Smith is in front of Thomas Smith and in the other one it is different."
The problem is that when 'sorting by lastname' is chosen we usually assume the second criteria automatically is firstname (or fullname).
Digging down in the code the second sorting criteria for quiz is attempt id and for assignment it is the submission date (forgive me if I'm wrong).
It would be great to maintain consistency and assure the normally supposed ordering lastname, firstname when ordering by lastname (and probably firstname, lastname when ordering by firstname) throughout all tables which can be sorted.