Doh, yes, unfortunately, that's my experience. It all depends upon the grade of stainless. For yachts, the only specification I choose to use is 316, equivalent to A4, which is stamped on the heads of bolts and other items using this quality. 316 stays good-looking under severe conditions of salt-water, sun and air. A more common, and less expensive, grade is A2, and you will see this stamped on the top of stainless bolts at your local hardware store. This has less corrosion resistance than A4, and in severe conditions it shows a light covering of the usual iron rust color. This is annoying if it is on such items as awning rails. If the oxide is removed, it will return in short order. I have a set of "stainless" steel stanchions round the deck of one of my yachts, and I discovered that they were not 316. They are always unsightly. For a particularly conspicuous area it might be worth cleaning such stainless, removing the oxide, and then applying a thick wax. Nick.
Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."