Forum .LRN Q&A: Confused about forum permissions

I know forums is now a part of the stock openACS, but since it's coming
from dotLRN, I thought I'd ask my question here.

I've been playing around with forums again, and I'm still confused
about the permissions.  I really want to grant the public permission
to read all the messages in my forums, but the only way I can see to
do this is to explicitely grant permissions to each topic in the forum
through the site-map permissions system.  I would expect that
individual forums would inherit any permissions I would grant to my
mounted forums package, but this is not the case.

Currently, I have forums mounted as /forums and I have granted "The
Public" the "forum_read" permission. The individual forums don't
inherit this permission.

Is this a bug, or a feature?  I'm hesitant to delve into the code,
because I don't know if this is intended behavior, and everytime I
have offered a bug fix for forums I have been duplicating effort.

Can anyone offer some insight?

On my installation, unregistered users cannot read forums by default, and I can't grant them permission to except on a forum-by-forum basis.  I am not installing dotLRN to do my testing, I am just downloading the acs-core and the acs packages required for dotlrn and then installing the core and forums with its dependencies.  I wonder if there is a package from dotLRN that makes forums behave correctly.

I did discover that the context_id of the forum object was null in my installation, which does cause the individual forums not to be able to inherit from the forum package instance.  Again, I don't know if this is expected behavior.