You all have some great answers. I realize this is a hard question to have a yes or no answer to. And yes TTT, your answer was within the OP. Thanks.
Interesting question and answers. If one finds out about a pending act of crime and knows how to prevent it, would he be required to notify the authorities? Is this legally analogous to the situation in the OP or completely different?
There was a similar and more ambiguous case a few weeks ago, when Symantec allegedly found out about the virus/worm attack (whose name escapes me at the moment) before anyone else but only alerted the paying customers.