I helped a mate install HID lights in his new mirage and noticed a little box on the firewall blinking away. It had 3 wires coming out of it, two running directly to the battery and the thrid being eartherd on the opposite side of the engine bay. He said it was part of the 'paint protection package' they sold him, electronic rust protection.
He let me pop the top off to see what was inside. A 555 blinking once every few seconds and a voltage trippler - diode, capacitor, diode, capacitor etc... It was intersting. I flipped the board and both earth wires were soldered to the same point. The output of the trippler was left floating. Do you think the dealer is aware its all a load of crap?
We use zinc anodes in a lot of our gear at work as it is all cooled via seawater. We replace the anodes every two weeks, more often in warmer waters. They do work but they need to be constantly in contact with seawater. We're told they shouldn't be used where copper pipe is used as the zinc plates itself to the copper and nasty things happen.