Couple things. Fall prevention training. Part of that is knowing how to rescue yourself if you do fall, what to do if your only option is to wait for help, and how to help someone else. There are training sites that will push you off a wall...
Fall arrest systems are meant to save your life when you fall. You don't hang in the air with them all day. That is a different type of harness. If you fall, you can't just get up and continue like nothing happened. Fall arrest part of the harness has to be replaced. The rest of the harness has to be fully inspected, if not replaced as well.
Hanging in a harness can kill you as the straps will cut off the circulation in your legs. To prevent that, there are these little pouches on a line that you can deploy from your harness that are basically stirrups. You can put your feet in them and "stand" up while waiting for rescue. If someone is in a harness and unable to rescue themselves, this becomes problematic. Gravity is a bitch and waits for nobody.
I figure it is just a display, but I guess they could go through the effort of shoving people off. Probably safer than the plane. Especially when you are responsible for inspecting your own safety equipment every single time you use it.