What I found interesting is that he didn't clip the lead to a pin stuck into the wet surface. He just clips it to a metal rod and holds it close. Never though of doing that.
The problem with this is it defeats the purpose of the clip lead and the electronics in the applicator. The idea is to have the bucket or whatever in the applicator at one voltage, and the surface of the glue a couple thousand volts different. The charged grass stands up as the fibers try to avoid other fibers at the same potential (voltage), and are attracted to the screen in the applicator if it is held close enough.
Clipping the lead to the track does nothing to the fibers on the surface, neither attracting them to the screen nor making them repel each other. You can get good results from the natural static charge of the grass, but it would be better if the lead were electrically connected to the glue
