In New Zealand the findings of the Transport Accident Investigation Commission are inadmissible in court proceedings by Statute. However the CVR or the FDR are not covered so therefore if the Police are bent towards a prosecutor wanting to make a name for themselves they have to get hold of one or both to use the information available on them.
The issue that crew have is the ability of a prosecutor with good theatrical skills to highlight a particular decision in which they may have weeks to pull apart a decision that a crew member may have had only seconds to decide.
Imagine a court trying to establish whether a Capt made a "negligent" to stop or go at V1 decision.