One person may die in the Sierra on an easy route, another on K2. They are both dead.
Yes.... and they made the choice to do so, in all respects. Thus no one but they should be held ultimately responsible for their death if that so ultimately occurs. That as well is IMO.
That is my point.
As a guide I would hope that you saw yourself at least somewhat responsible for assuring your clients' safety. If you didn't then you wouldn't be a very good one.
Guiding is a whole different issue and has no relevance regarding the OP and the death of one's chosen partner/s.
If my client is a complete newb, I am still responsible for their well being. If I choose to climb with someone that turns out to be the same, I can instantly suspend the activity and depart.
Guiding is held to a way different standard when it comes to responsibility. The client signs a contract (that includes many particulars) and pays a fee for a service rendered. Completely different than a normal climbing relationship between partners.