Using friend classes can improve encapsulation

[AlastrionaAdair]

My theory is that using friend classes can improve encapsulation when you use them together with factory and/or manager classes.

Say I have a class that is to unable to contstruct or initialize itself or I have a factory pattern where it is decided at runtime what object to create. My theory is by making the class that needs to be constructed befriend the manager/factory class will allow you to hide alot of class variables that shouldn't be directly accessed, while still allowing the manager/factory to initilize them.

This is my view on the subject but I would appreciate some input from other developpers.