Interesting you mention Saturn because believe it or not people are waiting in line for Saturns and Saturn dealers ARE marking up their cars. The basic response from dealers is that you can't haggle to get a better price, they will not sell for less than MSRP, but nothing says they can't sell for more than MSRP. Don't expect GM to help, their response is to remember what the "S" in MSRP stands for. Basically dealers are independent and they can set their own prices.
And some dealers brag that they don't add mark-ups but they require you to spend $3,000 to buy overpriced rims and other accessories.
The smart situation is a little different because you actually have both the manufacturer and the dealer network saying they will sell for MSRP and there isn't any real competition between dealers since they are all PAG.