Gradebook

Yes, the assignments DO inherit the visibility of the topic or weekly block (what you call section). So moving them to a hidden topic block (a block with the eye closed) is the same as hiding the asignment. But that hides the grades, which is something you did not want.

Steve is right that moving the assignment to an "unseen" block is not the same as hiding. Maybe I should have explained what I meant by "unseen" since it is not a standard term.

An "unseen" topic is a block with a number greater than the number of blocks shown. For example, if your course is showing 10 topic blocks, the content of blocks 11, 12, ... are unseen. If you move the assignment to block 11, Students will not see it. However the assignment can still be accessed by indirect means. For example, if you have an Activities block, then the Assignments link will take students to a page listing all Assignments -- including the one in topic block 11.

This is why I asked what you are trying to do. Are you trying to clean up your course page by getting rid of an assignment that is just taking up space, or are you trying to truly hide the assignment from Students--without hiding the grade?

AFAIK there is also no solution using roles. If you override Student in the Assignment context, setting mod/assignment:view to Prevent, Students will (a) continue to see the Assignment on the main course page, but clicking it will give them an error message and (b) they won't be able to see their grades.