Actually, the stands come eliminations were always packed to the gills. Dwight worked at the track, and was allowed to place his camera in different spots (Top of the iconic tower, suspended on a line over the track) but mostly filmed from the stands when it wasn't so busy. Take a look at his other clips. They're all worth a peek, and there's a mess of them from TF to FC to TAFC to TAD etc. Even some rocket car footage. May 9th 1981 was a Saturday, so I'm sure you folks that are looking for a chink in the armor will find one, but no matter what you say, these were some serious heady days of the fuel categories.
As far as the dry launches. Yup. That's the way they did them. It was a practice launch, to see how they were going to hook up, and drive accordingly. I believe the whole dry launch rule came about because around the time when tune ups and parts were changing, some teams would do them, some not. It was customary to know who you were racing, and their pre run sequence. If you did a long burn out, and dry launch/dry hops, you would begin long before the other lane, who would just do a shorty burnout and backup then stage. At this time, some teams would "accidentally" add a dry launch or long burnout when they usually didn't do one, hanging out their competitor as far as their routine, and basically, became a sure-fire way to get into their heads, but more importantly, mess with their temperature as they waited for you to finish your routine. The rule came when I believe, Pro Stock was famous for throwing in a full dry launch, with a slow back up which would really throw the routine of their competitor off.
here's a good example of Beadle's flopper having a tough time of it. Smoking the tires everytime he applied the throttle, so I'm sure he was really laying into the hand brake on the actual run, to no avail, it still lifted the wheels and lost traction.
Raymond Beadle AA/FC at OCIR 4-18-1981