Your point is murky. Usually investors are ahead of "the news." Some of the best examples of this are actually with Apple (go figure). The days after a major product launch the stock usually falls several percent. This can be attributed to the fact that people buy in leading up to the event and cash out afterwards. Analysts had moderate estimates for RIM's quarterly, they came in way under (making it extra funny they emphasized their "strong" earnings in their response) and their stock price fell 20% that day. They know their hurt, their investors now know they're hurting (they had an idea before, hence moderate estimates), the letter was aimed at convincing the public they're just fine. Honesty works, look at the recent Domino's PR campaign, sales are up after admitting their product was shitty.
