Custom iPhone camera controls (not using UIImagePickerController)

Question

While I understand that in order for an iPhone application to be accepted on the App Store, one requirement is that only documented libraries are to be used.

If this is the case, how are certain applications such as "Night Camera" and "Camera Plus" using a camera control that seems to be something other than the one contained within UIImagePickerController?

I have heard of certain cases where a developer has been given "special" access to certain headers that allow for features that would otherwise be impossible if constrained to only using documented libraries. However, given how opaque the application selection process is for the App Store, I would prefer to stick to what is recommended rather than take my chances.

Anyone care to shed some more light on this?