Found this thread again after watching Gangs of New York and doing a bit of post-viewing reading. Mental Floss has a nice article on the names of various NYC landmarks. Ahem.
You know, it's an interesting thing to consider - there is really a very little amount of empirical data on even something that seems cut-and-dried like this; most of the talk on both sides is really just "monkey see, monkey repeat," or anecdotal at best. I'm still a proponent of not breathing onto cartridges because the water in breath should oxidize the material; so too will the presence of salts if any carry on the breath (doesn't seem so likely though). However, the place I see rust most on gaming systems is on steel emissions cages in consoles...that must have been kept in garages. One other thing that might be a part of this: Corrosion from contact between metals. I don't know what's typical on NES cartridges versus the interior socket's connectors, but there have been cases of corrosion in computer hardware where the pins on a part connector (for example, the connector of a memory stick) meet another metal inside the connecting receptacle.
I'd be really rich if all the pennies in my pocket looked like the '55 doubled die variant there. In fact I could trade my entire collection of stuff (all of it) for a handful in my pocket, and be able to buy everything back...with change left over.
I'm tempted to say that's a myth. That would only be true of the older "painted-on" coatings, at most; I'm not aware of any modern coatings being degraded by what is essentially water vapor. One of the most professionally used modern cleaning tools, the Lens Pen, advocates gently blowing onto a lens surface to help the cleaning process.
Old coated lenses - the original bunch of 'em, all probably predating the introduction of autofocus systems like Canon's EF series (1987-present; a better run for a common electronic connector than the NES socket!), are simply more prone to wear than modern coatings, a bad situation which was remedied quickly. Having a coating that is easily abraded is bad for obvious reasons.