I find this a little unnerving about how many people are just so willing to lay the blame on new divers, pretty much wholesale. These are new divers doing their first open water dive. They are almost certainly going to be either nervous or overconfident, not many falling in between. Having only received OW certification they are probably not very aware of the fact they will be using significantly more air at 80-90 feet as they would at 40-50 feet.
I have also seen, and been in myself, situations where some concern was expressed either about a dive or one's own abilities and being told "don't worry about it". I specifically recall 2 situations where I told the dive operator, and then my dive guide, that both my wife and myself were new divers and being told not to worry about it, then my dive guide just up and left us. One went off to do her lobster hunting for dinner while the other led off the group while we were doing a weight check. I understand the dive guide helped the one newbie but he seems to have left the other on her own. Not smart.
I think also there are a few here that might be more adventurous than the run of the mill diver, especially those who are new to the sport. These type of new divers tend to put an inordinate amount of trust in the professionals guiding them, often to their own detriment. I think more blame should be placed on both the dive operator for allowing these new divers to go with an experienced group on a deep dive (which I find more dangerous than a drift dive, imo) and the dive guide not to signal the dive buddy to surface as well, and make sure the dive buddy acknowledged the signal. He is the guide. He is supposed to be guiding the group. A group is only as strong as the weakest members. If the rest of the group was as experienced as was stated then they shouldn't have been too troubled by having to go without the guide (just really losing the opportunity to spot some interesting things since they should know where they are going have been briefed).
I've gone without dive guides on several drift dives, or wandered off from the guide, and its no big deal. You are all going in pretty much the same direction. On a deep dive I tend to be more circumspect. I dive extra cautious myself since I'm with my wife and I am overly concerned about her well being. If it was just me I'd be considerably more adventurous but I'm more experienced in life so I look out for her. From my limited view I would think the male newbie was a bit overconfident (he was diving deeper than the rest) while the female was less sure of herself. I would also ask if these new divers had dive computers or watches. If not, how were they gauging their time below other than by air consumption or watching the dive guide? If by air consumption it is likely the diver had little to no clue how much more air he was consuming as compared to a dive for the same time at a shallower depth, so was checking his gauge less often than he should have been.
I think far too often in this Age of Liability people are too quick to throw the blame solely on those who really don't know better than to place it on those who are actually in the position of responsibility towards their clients.
Personally, if it was me and I was going on my first open water dive I wouldn't have gone on that particular trip but so many people really don't know better (they are naive) and believe what people tell them until the proverbial sh-- hits the fan. By then it is often too late. I bet the poor girl will never dive again and all because her buddy was arrogant and she was kept from doing what she was taught, which is stick with her dive buddy. YOU NEVER LEAVE YOUR WINGMAN MAVERICK! On every single Lesson for Life I've read in one magazine that is the number one reason someone dies.
I'm not saying the newbies weren't at fault. They certainly were. But I believe a certain amount of blame should be placed on the planner and guide for take more risks with neophytes than they should have. Thankfully they all got to live and learn rather than another tragedy under the sea.