Sacrificial Magnesium??

So.. I read somehwere thata good rust inhibitor for cars is to strap some magnesium (or other similar metals) to the steel body of the car, under the premise that instead of the steel rusting from the oxygen in the air, it steals the electrons from the magnesium at the expense of said magnesium....or.. something, kind of like a chemical battery.

Is this true or not? anyone with a good knowledge of chemistry able to confirm this? (i'm not too good with chemistry myself)

this follows with the sacrificial anode discussion of a few days prior. I believe that there was a linked site that gave an adequate description of galvanic corrosion and its prevention. If not, just search for "sacrificial anode" or "cathodic protection" on google.

if all other searches fail, these may be of interest:
http://www.diveweb.com/maritech/features/uw-su99.01.htm
http://www.howtobrew.com/appendices/appendixB-2.html
http://www.marfas.com/corrosion.shtml

(note that magnesium is high on the table, which means it is the one that corrodes when coupled electrically with any of the lower items on the list. Also note the difference between regular and passivated stainless steels, if you find a table that shows both)