I looked at this federal court case, and appreciate the comments above, which demonstrate the tug-of-war between the concepts of individual responsibility of certified divers on the one hand (with which I'm philosophically sympathetic) and the idea that the dive op "owed Tancredi a duty to provide a reasonably safe dive plan", which many above agree with, within limits.
I think the good judge let Tancredi off too easy on his contributory negligence, probably out of understandable sympathy for his parents (no spouse or kids here, and Tancredi, at age 33, wasn't a big earner, otherwise the damages would've been much higher than the $387K reduced to 309K awarded). He found that T, as a certified diver, "should've at least partially appreciated the (dangers of a 145' 20" dive)..and ..considered that it might be beyond his capabilities".
What he says next, I disagree with philosophically: "Once T boarded ..it's not reasonable to presume that he could have made the choice not to dive, even if he wasgiven some warning by the dive master. Once the boat left shore, T's only choice was to go on the deep dive with the others or sit it our, clearly a choice T could not be expected to make"
Oh, REALLY? T had been certified for 7 years, had dived Hawaii before, opinion doesn't say how many dives he had, or how deep, or size of tank or whether single tank (probably single 80 though). He decides to go buddyless to 145 feet? And brings a camera (according to the opinion, he took some pictures)? Many of us would say his contribution to this tragedy was more than 20%.
Also, no defense of waiver of liability was discussed. Wonder if he never signed one?
I've been on a single-tank dive to 140' (Hole in the Wall, Jupiter). Everyone on the boat had more experience than me (I had about 100 dives and a Rescue card). I sought and took advice from everyone and watched my gauges like a hawk.
Bottom line, someone should've talked with this guy on the way out, and he as a result should've decided to pass up this dive, whether on the boat or no. That's the trouble with only a one-mile ride out to a deep dive, not enough time to "interview" each other. Come to the Gulf of Mexico, a 130' dive is 20 miles offshore, you have LOTS of time to think about it and talk about it. I once took a novice diver down to 100' on his first ocean dive, but we'd really talked it over first, agreed on signals, how to check gauges, and "either of us can thumb this dive for any reason, no guilt, no questions asked". He did fine. Would I have taken him to 145? No way, nohow.
The usual disclaimer--I'm a lawyer, but this is not legal advice, yada, yada, and a federal judge's opinion, right, wrong, or somewhere in between, carries way more weight than my opinion anyway.