It's hard to sue DM for standards violation
A couple of years ago my dive team executed a rescue of a drowned (nearly drowned) diver who went OOA during an AOW course.
To make a long story short, the instructor wasn't even with the group and the DM *knew* that at least one of his students was about to go OOA and instructed them to remain at 18m/60ft until one or both of their tanks were empty.
The ensuing chaos was enormous and the DM cut-and-ran and left at least two of his his students for dead, which one of them would have been had my team not been in a position to rescue him. The other arrived on the surface with zero psi left in the tank.
And even at that... with the instructor completely out of control of his course and the DM panicking at the first sign of trouble and running away with his tail between his legs and squealing like a little girl, they both got off easy
How?
The instructor got off by insisting... lying... in fact, in a court of law (I was there and I heard it all), despite all standards and best practices to the contrary that he had no legal obligation to ensure that his students made it back to the surface alive. It was an AOW course and he argued that as certified divers they should have known better.
The DM got off by claiming... lying... that once the student went OOA (despite his role in the circumstances leading up to this event) his life was in danger and he had to choose between attempting to save the student's life and saving his own life. The court determined that no individual can be required to sacrifice their own life to safe that of another.
What REALLY happened was this:
1) The instructor badly planned a non-executable dive and told his students (6 in total) to follow him
2) students engaged on a "trust me" dive that resulted in 3 or 4 of them (of whom 3 survived without injury) running out of air before the dive was over
3) the instructor, regardless of standards, swam away from the main group during an AOW deep dive into deep water with 2 students, leaving the other 4 in charge of an incompetent DM on a platform at 18 metres.
4) When students were running low on air the DM refused to abort the dive and insisted on waiting for the instructor to return.
5) at least one of the students ran out of air at 18m/60ft at which point the DM panic-fled to the surface and left him for dead
6) one of his students, who also at this point had nearly 0 psi in her tank tried to save the OOA diver and ended up surfacing with 0 psi once it was clear that she was unable to do so
5) She tried to "convince" the DM to return to the bottom and attempt a rescue
6) the DM submerged but only decended (confirmed by his computer) part way to the bottom before girly-panicking back to the surface again and giving up. He subsequently argued in a court of law that he executed a search for the missing diver, which was a verifiable lie.
7) upon seeing the DM back on the surface again, the *student* raised the alarm at which point my dive team took control and recovered and saved the missing diver.
I won't tell you what has happened to that diver since then except to say that it wasn't pretty.
This whole experience left me wondering how badly you need to f-K up before you need to be held responsible... because clearly a series of 5 alarm f-k ups can be covered up by lying in a court of law.