I saw an MD 900 being marshalled in a bit too close to the edge of a ramp area where there was a fairly old panel fence which bordered on to a drop and then on to a 3 lane highway. We all saw what was going to happen, including the pilots as two 8 foot sections of the fence started to rock violently and then picked themselves up and went over the edge of the ramp and landed in the road. Luckily the traffic lights were red, so all the traffic was stopped. A couple of us jumped down and pulled all the debris out of the way, finishing just as the lights changed anf traffic resumed its normal flow.