@lewm I also wonder what the technology is behind these tiny things. They seem to be made from machined aluminum. If they were magnetic, or made from special ferrous metals that could interact with the flow of energy within the cartridge I could imagine how they work, but aluminum would not cause anything to change that I could ever envision.
I'm also surprised that Michael Fremer gave them a positive review, but I guess his findings were more positive than mine. His positive review is the only reason I tried them, in fact.