When inspecting a trailer coupled with a fifth wheel, what is a 'high hitch' condition, and why is it dangerous?

1. The trailer is sitting too low, causing the tractor's frame to bend
2. The trailer is too high during coupling, causing the kingpin to pass over the fifth wheel jaws and locking the tractor frame beneath the trailer nose
3. The fifth wheel is mounted on top of the tractor cab
4. The trailer landing gear cannot reach the ground