The ABC in Australia has dug up some 'expert' saying ( again) that the use of good night on the radio is very strange as it is not normal procedure. I wish they would give it a rest, there is not jining abnormal about it at all, especially when you are talking to your home ATC.
One wonders where these "experts" are found. Completely normal in practice along with others such as "so long" or "good day". In fact, it is so normal and casual that it sounds like a completely routine flight up to that point which is what led me initially to think that something catastrophic happened very suddenly immediately thereafter.