A bug I encountered with Quills weblog product is the weblog admin portlet being viewable to non-privileged users. This was not a desired result, so off to google I went.
Luckily there was already a diff I could use to patch the offending code in parts/instance/lib/python/quills/app/portlets/weblogadmin.py.

Here is the link to the diff: http://dev.plone.org/collective/changeset/52562/quills.app/trunk/quills/app/portlets/weblogadmin.py?format=diff&new=52562 . Patch the file and the portlet is no longer viewable to non-privileged users.