That's the point I am trying to make. The maneuver itself is not dangerous - so long as it is properly planned beforehand, approved and executed, like this one:
However, not having the clearance from the operating authority (the civil aviation authority of HK) is another thing, because there is simply no risk assessment on whether doing such a stunt at that specific location is safe or not, and any safety preparation can be requested to deal with any emergency that may eventuate.
It makes sense for FAA and NTSB to look at the case, but one key focus they will have is potential negligence from the tower controller as well as the pilots. There isn't much else they can do - the lead of the case should still fall under the relevant HK authority.
