With two ClassDB databases on the same server, and user1
is added as a ClassDB role (say as a student) to one database, but the same user is not added as a ClassDB role to the other database, user1
is still able to login to the second database.
In this scenario, a student user does not have unauthorized access to any object in the second database, but instructors and DB managers could.
I will add another comment soon with an analysis of the problem and potential solutions.
This issue is related to Issue #277.