I had no idea that the stairwell would be an issue until my great niece came over. She was about 4 at the time (10 now) and she stepped back at the entrance area and fell into the stairwell. We all jumped up and she was fine but it sure sounded terrible. We have an automatic cover (at least we and Dennis have one, LOL).... I'm much more aware of the smaller children that come over and make them aware of the steps.
One way or another, a step cover should be made and used over the stair area with small children around.
MM.