If you do a google images search for "running treadmill" you'll see most of them have some design aspect that would prevent the accident shown in the video, mos

If you do a google images search for "running treadmill" you'll see most of them have some design aspect that would prevent the accident shown in the video, most commonly a bar or guard of some sort that would stop a child or large object being dragged under. Edit: in case you haven't seen the video: https://www.youtube.com/watch?v=onXNnlCYJ4Y https://www.youtube.com/watch?v=onXNnlCYJ4Y