I have had my iPhone 4 for 3 weeks now and I got my apple bumper the day after I got my phone and now I have already noticed significant scratching and blemishes on the left side of my iPhones "stainless steel" band so I believe this is a definite issue wit these cases like apple states the bumper is to dress the iPhone up.
It is not stainless steel ..
It is brushed aluminum and it is the "brushed" part that scratches ..
Hard plastic and even your finger nail is hard enough to scratch this ..
It simply presses down the brushed finish and exposes the shiny nature of the metal when pressed ..
Yes .. the band can and does scratch the metal band ..
It is a well documented fact ..
My sisters phone WAS scratched by the band ..