Okay experts, please comment directly on this!
rust forms as a result of temperature and catalysts.
poached from the entertron...
Rust occurs when an area of an iron-containing substance drops below a pH of about 8.2. is common because iron combines very readily with oxygen. So readily, in fact, that pure iron is only rarely found in nature. Contrast to popular belief, water is not the actual cause of rust. Pure water will not cause rust to form on the iron. It is contaminants and alien particles in the water that cause electro-static charges (electrolytes), such as acid. For pH values below 4.0, iron oxide (FeO) is soluble. Thus, the oxide (oxygen) dissolves as it is formed instead of depositing on the metal's surface. With the oxide gone, the metal surface is in direct contact with the acid solution, and the corrosion reaction proceeds at a greater rate than it does at higher pH values. For pH values greater than pH 10, the rusting rate seems to fall as pH is increased.
I would reckon that in addition to having very hard water, his dishwasher does not get very hot, certainly not near boiling point, and he is using some sort of light-duty non-phosphate cleaner, and no jet-dry.
Products that "leave a streak-free shine" on your dishes contain certain surfactants and water-scavengers that will act as a catalyst towards rust forming.they also effect the PH as well.
this is EXTREME at higher temperatures and guaranteed above boiling point.
If your dishwasher has a "sanitize" cycle, as mine does, it is generating high temperature steam, and this will cause rust.
also, all non-rusting metals, like like phosphorus treated steel, parkerizing, nickel plating or stainless steel, don't rust because the coating creates a barrier. Once that barrier is compromised, ie: through scratching, it can rust.
Finally, stainless steel will rust in the presence of iron, so if you have some other metal, bare metal, iron, steel or a part with some rust on it, and that rust comes in contact with your "clean" metal, the risk of contamination exists.
I suspect that in the case of these chinese norinco's the parkerizing is not the best quality out there to begin with, they may have surface steel dust or shavings on them as a result of the manufacturing process, the medium oil may even have bits of tramp-iron contamination in it as well. These are all sources that can start and propagate rust under hot and humid conditions.
would be in order here hehehehe 
