OK, I guess that the discussion of this thread has more or less died down. Having been personally involved, I have a few more pieces of information and thoughts to share.
1. Several people asked if the SMB line that had been used for the descent was still in place. I am not sure if it was, but the instructions during the briefing were to make a drift ascent and to deploy one SMB for each buddy team so that the RIBs could find us. There was little or no current, so everyone surfaced within a rather narrow area. I don't think that anyone used the line for ascending, and the victim most likely didn't even know where the line was attached.
2. Much attention has been paid to the decision making process by the victim, but very little to the role of her buddy, K. I have a nagging suspicion that he may have played a direct role in the accident. He could have misinterpreted her signaling a cramp, which would have been unlikely to begin with since there was almost no physical effort involved in the dive. He may have bungled his intervention and inadvertently ripped out the weight pocket. He may have signaled to the victim that her weight pocket had fallen out, and even pointed down as it was falling. He may have panicked himself and precipitated events. I personally don't trust him to have told the whole truth after he surfaced. As I mentioned I had had a run-in with him after an earlier dive where he had behaved in an irresponsible manner, and he refused to acknowledge that he had done anything wrong. Others who had buddied with him pronounced him "unmanageable".
3. I have often seen people on Scubaboard stating that the only useful role of dive guides / DMs is to make coffee. In this thread, many faulted them for not having intervened either before or during the dive to discourage this buddy team from making the dive or to provide them with extra surveillance. The diving on this liveaboard was not advertised as being guided. and IMHO the DMs did perform their job well by giving good, detailed briefings and being present during the dives. Btw, there were no true beginners among the guests, just divers with different levels of self-confidence. I thought of offering the victim to be her buddy during this dive, because of her apprehensions, and maybe I could have prevented this chain of events. But I didn't.
4. After we docked in Hurghada, the police and the local court started an investigation of the accident. They interrogated all of the guests, as well as the DMs and some of the ship's crew. Together with the DMs, K. and two other guests I spent the night at the courthouse, mostly waiting to be let into the judge's august presence. They tried very hard to make us pin responsibility on the crew, on the DMs, or on the boat's owners and operators. Everyone said that they did their jobs well, and were not to blame. The case was finally dismissed. I fully expect that the insurance companies will take over now.
5. I went to the victim's funeral on Monday. The church was packed, and two priests showed up (one was a friend of the family). The victim was a universally loved person, active in her church and in civic life, member of local societies, and so forth. We should never forget that we are talking about real people here. I note that no one on Scubaboard was disrespectful.