I used to that for work years ago, you learn REAL QUICK how to keep your head and not freak out with the exposure. I highest I climbed on a tower was about 1100ft. It gets interesting when it's windy and the tower starts swaying.
It's funny how many different websites I've come across with this video. They are in total violation of OSHA fall protection regulations and they lie when they say their actions are legal. When they use the equipment they have, they exhibit total cluelessness with poor carabiner and hook usage. If they want to act stupid and unsafely, fine, that's their business. To video record their actions and post it to the web takes things to the next level. I'm sure their employers got in a ton of trouble and probably fired them.