I think this is a dumb policy on the part of CO. I would be more willing to buy from Delta than CO. Why do you think all the large retailers like BestBuy and Circuit City has 30 days low price guarantee?
These airlines do not care about customer satisfaction.

AA has the same policy as CO because I couldn't get a refund from them last year without a $100 fee, and the saving was $98 so no refund. Will I buy from AA again? Not unless it is much cheaper than the others.