I propose that we 'cut the Gordian knot' and replace the IFMC definition with the one implied by the 'Folk' section of my local branch of HMV:

ie. 'Folk music is any sort of 'acoustic' music, although it excludes 'acoustic' 'Country Music' and includes 'Folk Rock'. The term also embraces any sort of music which doesn't fit in any other category, for example the music of military bands.'

There! That should keep many of the contributors to this board happy, and they can now perform anything they like in a folk club (although why they should seem to need permission from 'higher authority' to do so continues to puzzle me).