C.G.
Vicks is not absorbed into the skin, it works when it is inhaled into the lungs. If putting it on the feet works, putting it on the chest should be that much more effective! Although I have heard this one before as well, there is no logical reason that it would work at all. Also the Vicks Vaporub website says not to cover the Vaporub with bandages or anything tight so I am guessing if anything putting socks on would make it work even less.
I usually put a lot of trust in mom-approved remedies but this one seems pretty silly to me. Also, FYI Vick's Babyrub does not contain any medications, just fragrances, so it is unlikely to do much at all. For my kids with congestion we usually use a hot shower running with the bathroom door closed. Here is a link to the Vick's website: http://www.vicks.com/babyrub.php