Regarding low flying risks, it is my personal experience (admittedly at groundspeeds under 150kts) that the lower you fly, the easier it is to judge height above ground and obstacles. Buccaneer and Tornado pilots who have operated at low level might wish to comment. Certainly video exists of operations at heights where wingtip vortices are visible on the ground, and I am not aware of any instances of hitting the ground when flying level. Rocket firing dives are another story.