Can Buying a Stock That Gaps Lower Give You An Edge?

How many of you have turned on your favorite financial news show to hear a list of stocks that are set to open higher due to "bullish news". You're told stock XYZ is due to open 10% higher than it closed the previous day and shown a crowd that has gathered around the post where XYZ's market makers are eagerly awaiting the market open. If you own the stock, you're probably thinking this is great news, and if not, you're probably thinking about buying it. But then you think about the last time this happened and recall how the stock actually closed lower that very day. So what happened? Surely all the bullish news means XYZ is going higher...or does it?