Cable "burning": Real or VooDoo ???

Yes, sloshing electrons through a cable changes it: the cable heats up. Temperature changes mean physical changes. Physical changes can change electrical characteristics--work hardening is an example.

Steve: I grant your point that heat in your example appears unlikely to make much difference. My point was in response to somebody previously who said electrons sloshing through a wire make no change to the wire. Heat cycling is just one example of a change-inducing physical effect that electron sloshing does have on wire. Maybe there are other effects not related to heat. And, given the subtleties of the differences we claim to hear, maybe it doesn't require much of a physical change to make the cable audibly different.
Also, relating to your example--I'm not an engineer, but couldn't the amount of power running through a speaker wire be substantially higher, enough even to create a measurable heating? So, even if a cable conditioner doesn't generate enough power to make a difference in your opinion, maybe burning in a speaker wire with real signal would at least push a lot more power through the wire and potentially have a much greater physical effect?