Hi Mark, Chung,
I think part of the problem is that you will not get a definitive (official) answer to this (maybe to do with liability) as when I did web searches all I found were blogs with various peoples opinions. Some were like Chung who had experience of using the clamp type carrriers without issue, others were dead set against it.
I suppose officially you could contact Ridley for advice but I could probably guess what the response would be
My experience was really formed when I did a trial clamp on my frame and I chickened out before I put any meaningful pressure on the clamp as it just didn't seem to be the right thing to do and it doesnt help that CF frames tend to have non-regular profiling on their tubes either. This was before I did the web research which put me off further.
Given the chance I would stick it in the boot.
Sorry know this is no help