Glen McFarland on the practice day at the Corryong Cup was flying in buoyant air trying to get down. He sped the glider up pushing the bar back until he was straight arming the glider at 130 km/h. Going that fast (beyond placard limits) he broke one of the down tubes on his Airborne C4-13.5. He was able to successfully land the glider with some slack wires.

Hang gliders don't have yellow and red lines on their air speed meters. The theoretical loading on the wing if it experienced a gust load and was reduced from 130 km/h to 30 km/h (stall speed) would have been square of (130/30) =  19 G. This assumes that the glider can't absorb the shock loading which is more true in the newer topless gliders (which are more like rigid wing gliders). Previously hang gliders were "softer" and this wasn't as much of a problem. The new topless gliders are very slippery and you can get them going very fast.

The lesson here should be obvious. If the glider is designed for a 6 G positive load then don't fly it faster than 2.45 times its stall speed.