I was offering a possible explanation not excusing what happened. If you don,t think it's possible look beyond D&G and check out the YouTube video on children of the magenta. Rnp is meant to be done on managed and does even more to turn the pilots into systems monitors than just the autopilot. The ATSB started looking at the implications of RNP in incidents years ago so this will give them the opportunity to provide some safety lessons (hopefully).