Can graders be prevented from seeing names of students?
A particular user, e.g. a Grader, can be prevented from seeing other users' names by assigning him the secondary role of Restricted or Very restricted. A user with either of these roles cannot see the first and last names, or email addresses of any users. Likewise he cannot access profiles, or send messages. (A Restricted user sees only ID number; a Very restricted user sees only Moodle ID.) The role can be assigned at the level of the course or in a particular activity e.g. Assignment. (If assigned in an activity, the activity should be locked in the Gradebook until grading is completed.) This is a HUJI feature.
Alternatively, all course staff can be prevented from seeing students' names in a particular Assignment by setting it to use Blind marking. If set, the assignment is effectively locked in the Gradebook i.e. the grades are not updated. Blind marking can be unset by selecting Reveal student identities (from the Grading action menu or Assignment settings.) Once unset, or if not set before the first student submits, it cannot be set again.