Our daughter was injured by glass in a club and required medical attention including sutures. She was shod in fancy dress heels, and the stranger she was dancing with in men's dressy shoes. He had stepped on glass which became imbedded in his synthetic sole, and when he clumsily dragged his shoe across her bare instep he sliced it wide open with blood streaming onto the floor. Had HE been barefoot, not only would be have had healthier feet, but he would have been aware the second he stepped on the glass and either had no injury or a minor puncture/laceration. Either way, no chance that he would have ended up using the glass in a way that ended up causing REAL damage.
Another case for REQUIRING bare feet for entry in the interest of safety.