That was a nasty trick by rumor monger. They blasted a rumor by using text messaging to start a run on BEA on their Lehman exposure. Then they sent out a fake letter to do the same to AIG.
another rumour is that some hedge funds short BEA's shares beforehand and deliberately spread bad news thru sms messages to local people so that they can benefit from BEA's price fall btw, there's still long queues outside the Bank's branches
In these situations, it seems free speech has been blamed, and over-use of leverage has gotten a pass.