In my book, non-punitive means coming forward with (potential) encountered dangers during the flight which without the report would not be known to anyone. This was not applicable in this case, since ATC notified them of the mishap - without a report from the crew, the incident would still be known.
What is interesting, is that - perhaps conveniently- the CVR "event" button was not pushed afterwards (contrary to regulations) ; so any cockpit conversation was not available anymore to the investigators.
Maybe the crew was not having a silent cockpit/ F/A chatting away on the flightdeck? Nobody knows. Smart game from the crew if they knew they were distracted for whatever reason..
What do we learn from this? Keep taxicharts ready, which is a standard in most airlines anyway.
Thank God nothing actually happened.