I have a Custom CDP II (w/ Schwartz Safety) and haven't had any problems. As I understand it, the integrity of the system is only at risk if you forcibly reassemble the gun incorrectly after field stripping. On a Series II Kimber it is important that you not depress the grip safety when you install the slide onto the frame. Forcing the slide onto the frame while the grip safety is depressed will require significant force & can damage the safety mechanism. In fact, it requires so much force that it should be obvious something is wrong. Just be mindful of this during field stripping and you'll be fine.
I was oblivious to this for the first 3 years that I owned my Kimber and I never broke it.