Aus380. I think you're caught up in the typical self importance that exists on the 380 in Qantas.
Of course people court letters as GalleyHag suggests.
From what I have heard, OBM's on the 380 are generally the corridor creepers who would also try and persuade pax to write a letter when they are happy. Of course the reverse would exist if there was a dissatisfied or disgruntled passenger on board.
Management need to take a good look at themselves if they are promoting on the basis of letters in ones file, or how much one brown noses around qcc1. When the original OBM's went to the 380 at initial introduction, I'm sure that brown nosing was a pre-requisite!