From a rest/risk perspective, let's not forget the other airlines also have 2 capts and 2 fo's who are current....Qantas will have only 2 current/qualified pilots who can land, and two SO's who while no doubt could get the job done if need be, will have spent all their time in the seat above FL200. With TOD's this long, surely adequate rest is something that must be considered. Rest doesn't necessarily mean sleeping either.