Never seen a misclick-panic before?
They always remind me to check I'm using the correct sell/buy box on Gox, they look so similar.
Some people panic after they mis-click and do the opposite move instantly afterwards.
Or they really want to trigger Bitcoinica. these only go one way though, if I understand correctly, because it's a bucket shop if it can be. Can't say what kinds of exploits exist for certain though, I don't use Bitcoinica.