" calling people on the PA without their rank is rude, be it Private or Wing Commander "
I remember an incident many years ago when a passenger clerk at Akronelli attempted to call forward a passenger using his rank, name and regiment. Unfortunately the passenger was of the Mexican moustache variety from the Welsh border area and didn't want to be identified. After a number of unanswered calls the clerk was taken away to a quiet corner by the DAMO and given a rollocking.
Perhaps it would be safer to call all passengers Mr, Mrs or Ms.