pennys in trunk Trick

Ok guys, I have one for you. Whats the deal with the pennys in the trunk trick? I was cleaning out the trunk in my new 92 svx and found about 150 or more pennys in the trunk. They were placed in all areas. They did show oxidation so i am thinking that the previous owner put them there thinking that they will stop the trunk area from rusting. I have a boat that uses a Zink plate to stop other parts on the boat from rusting, Will copper do the same thing? The car is from Ma. as you know and there is alot of snow in that country. Oh and the hell of it is that it seems to work.. The car has no rust In the trunk or any where for that matter. Was the guy nuts or is he on to something? Jim Stanley