This is very strange. It could be that there were so few hits on it anyway that obsessive clicking on it by Jared Loughner caused the dramatic change. In any case, it's odd.
It could be that there was increased interest prior to her public appearance, and there is also the 'global consciousness' phenomena that is evident before dramatic/pivotal events. I think there is a damn good chance that some were 'compelled' to visit the site, without necessarily being aware of why.
Just a thought.