I have several points.
1. The story just hit the news although the incident happened on January 5th.
2. If you would do a Google search (which most posters here apparently have not), there are different stories from different sources. The only version that I have seen on this thread is the parent's side of it. Perhaps not is all as it appears????
3. I would be interested to see the receipts for the entire cruise. Here is my reasoning. The incident happened on the third day of the cruise. Was Lynsey behaving and not being served drinks on the ship until the period just before she went overboard or was she being served prior to the period in question? If she had been being served, did her parents know about it? Perhaps her father had informally "authorized" the drinking on board. I have seen this happen. That would not excuse the bar staff but it would shed a different light on the parents' contribution to the incident. Also, the parents could have checked their current bill on their cabin TV set. Were they checking periodically to see what their kids were charging or not?
4. The family has quite a bit of money and are probably not suing for the money. They are offering 205,000 EURO reward for anyone who finds the body.
5. I am not a lawyer, but I wonder if the fact that Lynsey was returned safely to her parents care after she became drunk but before she went overboard means much. From the ships viewpoint, wasn't their liability limited when her parents took her back into their custody? Why didn't they keep a better watch on her and take better care of her?
6. One of the stories said that she might have had an argument with her boyfriend and did not fall off of the ship but jumped. If this is true, did she argue before or after her parents took custody of her?
I don't think that anyone can answer these questions, but without answering some or all of them, I think that there are too many unknowns to have an informed opinion of who is to blame.
JMO