Well, I wasn't really talking about a event where the existing users would flood the system with transactions. I thought of a event where a lot of people would become interested in Bitcoin/join it. However, the example linked also applies. Even though that is a concern it is not worth risking the whole system over it. I do wonder though why the Core developers don't bump to 2 MB; if we consider all the research done so far I don't think it would have any harmful effects that (too) big blocks might have.