Yes, I understand the types of licenses, I am just conveying the path that TRU used to (and may still do) take. Getting the rights cleared from the creator for a specific use was done to ensure that TRU resources could be published with all rights reserved.
One of the issues that causes traditional univesities grief is that once you include an OER into a course than the course must conform to the Creative Commons licence of the original OER. Therefore if TRU even re-purposes the content they must make it available (without restrictions) for others to download. Otherwise the institution violates the licencing agreement.
Now that being said, I am not sure who enforces this policy. It would be a very difficult task to follow the different re-use/re-mix variations that are based on single OER.