Where did this 0.1% come from? Again, you are reaching. There is ALWAYS some sort of risk. There is risk in their own equipment as well. Doing the diligence of properly serviced gear is all that is needed. There's an ulterior motive here. That's it. For me, that's a red flag.
Actually, I have a number of lawyer friends who are all quite honest and have integrity. I also know of some lawyers who if I found bleeding to death in a ditch, I'd go look for branches to cover them up. Initially they will sue everyone that could be liable. As time goes on, some defendants could be dismissed, like what has happened in the fatality in Glacier National Park that David Concannon is the attorney for the plaintiff.
I am liable for my actions, how I conduct my courses, whether it is open water or not. I have only two open water students as I only have two hands and will always be in control, but I will also ensure competence before embarking in open water. I am under no pressure from any shop to ram them through certification, so I reserve the right to terminate training if a student is uncooperative/has a bad attitude, is an accident (or worse) waiting to happen.
There is always risk when going into the water with untrained individuals. As well as poorly trained individual. It is my duty to mitigate those issues. If I do not believe I am able to address those issues, I opt not to teach.
If you make a claim, you have to back it up. I've had insurance through V&B and DAN. What both address is whether I provide my own gear or not. If I do, then I need insurance for that as well.
We have to use both prudence and common sense.