The use of a single "primary_ccn" is a tip-off that something is still a little wrong in the design. The Campus Roster viewer has to work for the following scenarios:

* The user is an instructor in only a primary section.
* The user is an instructor in only a secondary section.
* The user is an instructor in multiple primary sections.
* The user is an instructor in multiple secondary sections.
* The user is an instructor in one or more primary sections with implied access to nested secondary sections.

So any place where we assume the existence of one and only one primary section is likely to indicate a bug.