While I do have a belly I think I will pass on this kind of engineering. I do not see the proper supports if the main support should rail and cause the person to be dragged off the bench and injured in their sleep. It is no fun when you fall off things in your sleep. It is my opinion that many bellies are being hurt due to unapproved engineering feats that lack the safety and proper tools to see them safely installed to prevent belly injuries.
Yes, and depending on the height of the bench, if the belly reaches terminal velocity it could cause injuries to any under it or to the foundation.