Well, technically, no one ever said 'the end of the world' in 2012. What they were really saying was 'great change will happen' which means anything..well, great change! xD /nerd
What I think? Well, I do believe that whatever happens, people will go CRAZY a few months before December 21st, 2012, because of fear. And that itself could cause some disruption, depending on how bad they act.