As someone who used to write reports on cave diving fatalities for the NSS, I understand some of the problems involved.
- Some people do not want to talk with you about what happened. That could be for a variety of reasons, including a fear of not looking so good.
- Some people will provide inaccurate information for a variety of reasons, including how it will reflect on others. They don't want you to write something that may make someone they like look bad, and (amazingly enough), they don't want you to write something that may bring credit to someone they don't like.
- There is a genuine fear that even your truthful relating of facts can lead to a lawsuit by someone who says your facts imply misplaced fault.
I once did in-depth interviews related to a near fatality, and I got two very different accounts about one aspect of it from the people involved. The critical one (the survivor) told me that if I even mentioned the other person's version, he would refuse to authorize the use of anything he had told me, which was 100% of the information on how things originally went bad. I was (and am) absolutely certain the other person was telling the truth, but eventually it was decided that account could not be included.