I was reading the How to survive thermalling in crowds by Joe Greblo and noticed the word "predict/unpredictable" appear 6 times in the article.
http://blog.rodbailey.com/archives/86-H ... reblo.html
"Consider for a moment how 200 people can safely ice skate at a crowded rink IF everyone conforms to basic patterns of speed and direction. But remove 100 of those skaters and send the remaining 100 on the ice to race around in any speed and direction they wish, and the ensuing ice anarchy would result in utter chaos!"
[youtube]http://www.youtube.com/watch?v=Xj5nsoKahMI[/youtube]