Here is the scenario:
Assy. C contains Assy B. Assy. C is open read only. Assy. B is opened from C and modified by adding a part. Assy. C is changed to writeable using reload. Upon reloading Assy. C, Assy. B is also reloaded removing the changes to it.
This does not seem right. Changes to a top level assembly shouldn't cause a lower level assembly to change or reload. Had assy. B been saved prior to reloading assy. C this would have gone unnoticed.