That was a great one. With all due respect to the deceased, it sounds like this was a situation where the proper precautions were taken, the conversations were had, then a renegade member of the group (who also happened to be the most qualified and honestly, probably about as qualified as you can get - I mean c'mon, a graduate degree focusing on snow studies, how many people have THAT?!) chose to ignore those precautions and discussions to seek a sicker line.
I have minimal backcountry snow experience, but a ton of backpacking and general woodsmanship experience. Mother Nature is beautiful, enchanting, but that bitch will turn on you in a second and often doesn't grant second chances.