When I was in high school, I worked the last summer for an excavating company. One time we were digging a hole near a sidewalk, and they didn't use the digging box, they said it wasn't that bad. My friend had the sides collapse on him. I climbed out in time, tried to pull him, but I couldn't. They ended up getting the fire and rescue people and digging him out. I stopped working for the guy after that, big OSHA investigation anyway. That was enough for me.