some 70 people still would be alive if one of the two crews would have reported what they are doing. They both descended, one ordered by ATC, the other by ACAS (TCAS)
That's the one to which I was referring. Had they both done what TCAS told them, there wouldn't have been a problem, no need to tell ATC their intentions. However, one crew was trained to obey TCAS in case of conflict with ATC, the other was trained to obey ATC. Now they're all trained to follow TCAS, so they shouldn't collide with the other aircraft involved. Of course, that doesn't stop a secondary alert being triggered as they move into conflict with other traffic.