buff ... see the response i posted on the third post
I can appreciate that the ropes being made today more than likely exceed our expectations of catching big falls and limiting energy; far exceeding the standardization process. Certainly, there is room for the argument of how much the pro or climber actually sees for force in half-system or twin-system applications, how much a climber gets in elongation, or how static is the belay system in reality. Compared to the marginal terrain situations we enter into, the ropes are the least of my concern.
So I can agree with the confidence of the manufacturer in that the ropes will more than likely perform to what we subject them to. However, there does seem some over-confidence to then apply that to the overall system behaviors in what this topic addresses. I just don't see the basis.
Take two independent systems that will behave differently when the fall energy hits but force them both into one mid-pitch component like a small lightweight biner -- how is that a good thing?
Got a reply from someone at one of the two companies I emailed. Off the record he said he has not heard of a rope failure by doing this, and has done it himself without any problems. However, [he agrees] that it has not been fully tested/investigated.
Interesting. Rope failure per se wasn't what I was concerned about but rather the glazing/burning of the sheath. My still untested hypothesis is that someone who makes a habit of combining twin- and half-rope clipping technique on each pitch (and falls a lot) would trash his rope more quickly than someone who sticks to one method or the other on each pitch. I guess we won't know without drop tests or other evidence. Carry on and clip however ya like.