A few years ago I was at Grand Canyon at one of the overlook points. A young girl was trying to do a selfie. She kept backing up to the edge of the cliff. It was obvious she did not know how close she was. It was several hundred feet down. I walked over and grabbed her arm firmly and literally jerked her back from the cliff edge. I then pointed to the cliff.
I could not communicate with her as she was Chinese. She was a pretty little girl doing stupid things. As mentioned, I could not communicate to her after I pulled her back. She did not object to my actions. She was about three feet from death and still walking backwards.
Last year my wife and I were in Yellowstone. My wife was braced against some rocks taking pictures at the big falls in the park, but I yanked her back a couple of feet because a busload of Chinese tourists had entered the observation area and were bumping into everyone while they backed up with their selfie sticks. It was a long way down...