Turns out that they believe the arms are passive (read the article for a slightly more technical description), and are not used to help propel you. So all that excessive arm swinging is not going to help you run faster - you're better off letting your upper body move naturally. A while ago I experimented with different arm positions and swinging techniques, and discovered that if I kept my elbows bent at greater than 90 degrees and close to my chest, and didn't try to actively swing them, it felt more comfortable and efficient. So I'm sure Dan would be relieved to know I agree with his findings. Now he can sleep much easier.
I was a big arm swinger when I first started running
Are you a running windmill? How do you move your arms when hitting the street?