at some point in the design stage of the walkway it had been suggested that a system of electronic sensors and automatic barriers might possibly be installed , the idea being that should the sensor detect the presence of a large - or small - body , in a position considered too perilously close to the exposed sheer drop at the edge of the high ramp , then a protective barrier rose from its concealed position beneath the walkway preventing the object from placing itself in a position of further harm .