Homefront from THQ is a good example of this. Only scores above 80 were released prior to the "supposed" PR embargo. Scores were in the average 80s prior to embargo, then plunged once the embargo was lifted. Then the game comes out full of crashes, lockups, server issues, and a 5-6 hour single player campaign. If you want to see overselling, just search for "Danny Bilson THQ."