electrolysis is the result of two dissimilar metals, in the presence of an electrolyte, having an electrical return path that allows current flow, and thus ion transport - otherwise known as "erosion". cooling system erosion is passivated by using a [quality] antifreeze and by avoiding a source of free aquatic ions, i.e. tapwater.
since the return current paths that facilitate erosion [in the case of "disabled" antifreeze] are all internal, e.g. the direct physical contact between a copper core and a solder seal, or even the atomic solution between zinc and copper atoms in a brass alloy, i have a hard time understanding how "grounding" could possibly help since all current flow is inside the cooling circuit. unless you add some kind of electrode [like cathodic protection on ship hulls] to the system to impress a stronger current over existing potentials, i think the adherents of "grounding" are simply misattributing their "success" with using it from the fact that they're actually paying attention having previously had problems from neglect, and are now also changing their antifreeze on schedule...
bottom line, don't bother. just make sure your antifreeze is kept up to spec, do NOT dilute or top up with tapwater [use distilled only], change it every few years, and you'll be fine.