As the PIC on an instrument training flight in IMC, I may not be manipulating the controls for the whole thing, but I am still on instruments myself. If we exoanded the argument further using your logic BEagle, none of us should log any time when we are with a student, but we aren't actually flying the machine.
At all times no matter what the conditions, we must be ready to take control, we are monitoring and keeping ourselves in the loop.
How would you define someone on a Cat 3 approach? Afterall, you aren't allowed to hand fly the thing under these conditions and yet you are solid IMC down to the deck, should you not log the IMC time?
Personally I think these arguments slightly spurious, since unless the CAA has an exact track of each flight and an exact copy of the weather at the time, who can actually judge whether you were IMC or not? People could claim for anything and there is no way of checking.