Given some of the responses in above posts, could I just try and adjust the thrust of my original post.
There was no failure of humour, I too found the phrase SLF funny, as others have said its an 'industry in-joke' - my thought/question however was two fold -
Firstly was it good for an industry to have no clear/respected? target/market for its wares and services apart from this acronym -
Secondly with the current rampaging union problem with its lies/spin machine and the rifts they have tried/succeeded in creating between CC's internally, management and apparently in some cases with flight crews, SLF could also become a target for vitrol to the detriment of the operation.