Scott - not meaning to be confrontational and I stand to be corrected but my understanding is that the airbus avionics will not lead the aircraft outside the airway, it has predicted accuracy etc and will use all the airway it can be sure of but not more. Are you sure a Bus has been more than the 5 miles out? Just cos it aint boeings way doesnt mean its the wrong way. I was suspiious at first but now with plenty of bus hours it aint never been wrong...
Terrain safe - for a vast majority of 320/1's out there has to be range from a point we are going to (next/one after etc), if it isnt then its time to select in a VS with some dead reckoning by the pilot, abm points not (practically) possible. New 320/1's are available with a better box (cost option) that does abm points a la boeing (330 has always had the ability).