As stated Annex 13 is not legally binding and each state has to enact its own legislation regarding accident investigation. In Australia the TSI Act gives specific protections to the information provided to the ATSB investigators to the point that any information provided cannot and will not be used against you. If the information is divulged by the investigator they are the ones put in gaol. Unfortunately the media in Australia will usually state that CASA are investigating which is not the case.