Essentially,it's been in place in the UK's Mandatory Occurrence Reporting (MOR) scheme for many, many years. How it works and how much people are prepared to report 'that was nearly very nasty' type incidents depends on the way that the reports are handled....and you only find out after experience.
In the UK MORs normally go through unit management before they get to the CAA. At one unit I worked at the manager would do everything to stop the report going further - even within the company - and always looked for who to blame for the incident, typifying almost the reverse of a Just Culture. Fortunately the UK scheme allows you to submit a report directly to the CAA in confidence and my experience of the way that the CAA handles the reports is nothing but positive. I have seen potential problems resolved through such reporting long before 'the incident' occurred.
It's all down to the people involved.