I'm wondering if CREATE_IF_NOT_FOUND should == DETACHED_CATEGORIES. I notice that the course_details.py update method creates 'about' ones if not found. I didn't look into the static_tabs, but I think they're created currently by the couse_module __init__ method if not defined; so, it may be at least safe to treat them similarly. DETACHED is also weird b/c it doesn't mean they're not pointed to, just not pointed to by children field.