The answer is that you would also be breaking the signal return path.
I thought so, but it was unclear to me what the audible results would be, which the rest of your answer describes very nicely. Thanks, Al.
While the hazards of using unshielded interconnects make sense to me (particularly when they are unbalanced), my experience has been that I like the sound of unshielded interconnects. I'm currently using unshielded interconnects from Morrow, but I have also used ones from Kimber and Anticables. Like other listeners, I have experienced an "openness" with unshielded designs that is appealing to me. I'm not saying you can't get that with shielded designs, but I haven't had much luck finding it, except for a $2k+ pair of Synergistic cables that I owned for a while.
I'm not suggesting that unshielded cables sound inherently better than shielded ones. Just that I've had a easier time finding the sound I was looking for with unshielded designs, at least among more affordable cables. This could, of course, be an artifact of a small sample size.
And, FWIW, I have also experienced a similar improvement in "openness" going from a heavily shielded PC to a lightly shielded PC on my preamp, as reported by Lokie.
Bryon