All sorts of hazards are "grandfathered" in. If cars were invented today, they'd never be allowed. Now think about stairs. A certain athletic performance is ne

All sorts of hazards are "grandfathered" in. If cars were invented today, they'd never be allowed. Now think about stairs. A certain athletic performance is needed to rapidly descend stairs. Get it wrong and you can tumble a long way onto concrete. Life-changing injuries are just one slip away.