GoodThings

In this video: http://manifestmaster.com/video/vinton2007.wmv I am surprised by a few things I see. I'm a beginner trying to learn about skydiving and some of the stuff I see in this video confuses me. Several times in the video I see a guy "sitting" at the front center edge of a guys canopy below him. Is this common, or very dangerous? I'm surprised that the stunting would extend to canopy flight in this manner. Also, the "little" canopy above the rider (about 3 feet over his/her head) is tied up at some points. What is the purpose of this? Thanks for the answers in advance. Also, what are people who fly cameras doing about altimeter checks? Do they have a special altimeter or do they just really on others in air and visual to determine altitude? Are there requirements to fly camera or can anyone wear a cam helmet?