I was really uncomfortable watching that. I'm pretty sure it would have been swaying a bit too.
When his mate jumped on the top, the pole the other one was vaugley holding but hooked on to swung inside the frame it had, it was as thick as his fist and the frame was about the same distance away from the pole (you'll have to look again probably lol) - so that bit at least swung 8 inch just right there in one move. I bet the whole thing wobbles with not just the wind but them blokes must shake it too.
Had a similar height experience skiing, in a gondola and I nearly cried in front of about 30 other people. And that's knowing eveythings fine as it's been working for years with no failures. Jumping about outside though is a totally different story.
The voice over bloke was like "and climbers call this free climbing, meaning they have no safety harness" I thought, I call that crazy. I bet they throw their bag off with it's own chute, and base jump off it too, knowing a couple of mad heads like them I wouldn't put it past them.