Changing the rules is good if evidence emerges that the rules are bad. In this case, the $250k guarantee was thought to be enough to prevent this kind of thing

Changing the rules is good if evidence emerges that the rules are bad. In this case, the $250k guarantee was thought to be enough to prevent this kind of thing from occurring. We now know it was insufficient. The world has changed since that was implemented. Namely, social contagion, which is one of the causes of bank runs, can act harder and faster in the age of social media.