I'm not an accident investigator and don't know what exactly would turn out to be useful, but I think changing your intuition for why we study the CVR away from "because there might have been a large pilot error" to "so that we can learn more about how pilots react to emergencies with a goal of seeing if we can come up with process improvements" may help. If there was some aspect of the response that was not perfect, we could develop training on it for other pilots, right?
That's not what is at stake here though. CVRs are not intended for improving process like a call-center recorded line. "Both recorders are installed to help reconstruct the events leading to an aircraft accident." [ntsb.gov]
This creep of intended-use is exactly why many people oppose surveillance in the first place.
I don't understand. You're saying that the purpose of cockpit voice recorders is not to improve aviation safety via allowing a thorough investigation of accidents? If there is any other purpose, I don't know what it would be.
