S&P downgrade services gets paid very well for their services. Whoever wants to buy on the cheap hires them. Look at it like this, do you really think that the SEC wouldn't notice if GS, MS, or Pru downgraded RF and then they start buying the shares for the next 3 days?

GS, MS, all of them rely on 'contract services' for ratings. The price they pay is a drop in the bucket compared to what their potential gain will be.