Forum

There is an logic error somewhere, but I'm not sure if it's in my head or in the Moodle code:

I have several teachers on a course. I want to prevent some of the teachers from posting to some of the forums on the course.

On the course level, I have overrides for the Guest role: I'm preventing Guests from posting to a forum. Then I'm assigning the teacher to have a Guest role on the Forum. The teacher is, however, still inheriting the rights to post to the forum. Why? I think that the lower level role assignment should override the upper level Teacher assignment. I also tried Prohibit, and it didn't work.

Then I cleared the course level overrides and tried to have the overrides on the Forum level, but still the teacher is inheriting the right to post from "somewhere", though there is a lower-level role assignment and a role override saying that "Prevent posting". (Also tried Prohibit here).

Ok, I was able to work around this: prevent Teacher role from doing anything on the Forum context, then assign the "can-post-teachers" as Admins on the Forum.

But, why didn't the lower-level post prevention work the way I tried? Aren't the lower level "Prevent"s overriding the upper level "Allow"s?