I've been debating with and writing to the ANSI commitee for almost a year on this subject.
It seems that they are frightened that a clear common sense approach like mine would be misunderstood and result in an accident were it to be adopted and written into their specs.
They see two scary problems with my method.
1. There are many cranes that have no positive locking gates on their load hooks, this scares them silly because of the obvious danger of the lifeline bouncing off the hook.
It is my opinion that no crane should be allowed to work on any job without a lockable hook gate period. I won't work under a crane without one because I've seen the rigging come off the hook as the ball is lowered through a thick canopy on cranes without a locking gate, it's a hazard to both the climber and groundmen below.
2. The potential that a lifeline on the hook could be severed were it to become trapped under rigging hardware under load.
This is easily avoided by using two steel locking clevis' on the hook, one for the rigging, and one for your lifeline TIP. This allows both rigging and lifeline to be unaffected by the ball and crane cable spinning under load because both are on the hook below the 360 degree swivel specifically designed to minimize load spin.
The fact that very few if any climber deaths have occurred to date while tied into a crane has the ANSI commitee totally paranoid to risk changing their specs, and I am somewhat sympathetic to their point of view. In fact I myself am firmly convinced that only experienced journeymen climbers should be allowed to work trees down with a crane regardless of whether they tie onto the crane or not. The potential to get seriously hurt or killed working with a crane is very high, and as every climber knows, all it takes is one mistake or miscalculation, and its game over.
Work safe!
jomoco