There is no such thing as guaranteed safety, especially when one's own family may kill one. The nanny state is doing it's best to emasculate us all, but so far only partially succeeding.
People like Hillary must be spinning in their graves to see what has happened to NZ.
The trips to White Island were adventure tours, and as such were obviously hazardous. As I said before, it comes down to if customers were advised of the risk, and signed to say that they were.
Obviously, if the risks were not stated prior to the tour and nothing was signed, there is fault on the organisation's part.