Regardless how any of the pairs of speakers were attached to the amp, only those who had both a positive and negative lead afixed to their binding posts directly from the corresponding ones on the amp would play/work.
Yes. Of course. That is absolutely correct. But we are not talking about having only half the normal complement of cabling. We are talking, in fact, about having 1.5 times the normal compliment of cabling. The normal complement of cabling on one side of the amp/speaker interface (say the positive side), and twice the normal complement of cabling (two parallel conductors) on the negative side. Is that not clear?
As I understood your original suggestion, you were suggesting that to run a comparison between two sets of speaker cables, it was sufficient to just disconnect one conductor of the cable set that was not in use at any given time. So that one side of the speaker would be wired to the corresponding terminal of the amp through one conductor of one cable, and the other side of the speaker would be wired to the other terminal of the amp through the other conductor of that cable PLUS one conductor of the unused cable.
And my point was that you would then have a complete set of connections between the two terminals of the speaker and the two terminals of the amp, but one of those connections would go through two conductors in parallel, rather than just through one conductor.
Which would obviously function fine, but would make the comparison between the two cable sets meaningless, because on one side of the speaker/amp interface the current would be flowing through two conductors, one from each cable set. The current would divide itself between the two conductors in inverse proportion to their resistance.
That is not speculation and it is not rhetoric. It is elementary circuit theory. If you don't agree, then you are envisioning a different configuration of the connections than what is being discussed, or you are not understanding what has been said.
Please do carefully re-read the original poster's question, and my responses to it. The basic point that I can't seem to get across to you is that electrons flowing through a conductor (or two conductors in parallel) between the negative terminal of the speaker and the negative terminal of the amp don't care whether or not those conductors are physically part of the same overall cable assembly that contains the conductor that is connected between the positive terminals of the speaker and amp. Is that not clear?
Regards,
-- Al