[Margaret Pilkington]

Eric, I think you could ask Mick that one.
For me The FA bit denotes Football Association, but for it others it may mean something entirely different. I think that if you used FA without following this with 'cup' then you would get censured, but this acronym is in common usage and most people(you included) know exactly what this means....There is no ambiguity. The problems arise when other meanings are ascribed to acronyms..... Especially those that can be seen to be rude, lewd or otherwise derogatory and insulting.