Firstly, I appreciate the nervousness of some passengers at what was - unbeknown to them - a routine procedure conducted for their saftey. I have just been reassuring a friend of mine who was doing LHR-YYZ with AC yesterday and had a turn back due to (stated) auto pilot failure). They returned LHR for replair/swop. She said that she felt very nervous because she did not understand. Of course, it is not easy to explain certain failures to folks.
To this incident, given that the senior cabin crew does not know the reason for the G/A, under what circumstances can the senior CC give a reassuring P/A?