I don't see any mention of doing it that way in the CodeIgniter user_guide but checked the function and you are right.
However, this has changed in the next version of Redux 1.4 because it will take out the autoloading of the libraries. This is because it's easier to keep all the loading of libraries in 1 place where you know they are loaded, autoload.php
Kind Regards,
-Mathew Davies.
Ps : 1.4 is still in the works and nearly done. Thank you to the person who reported some bugs in the Google code, it's appreciated. I've been busy with clients in the last few weeks so that's the reason for a lack of updates.