What a lot of ' folkies' seem to miss out on (and this is BOTH sides of the Pond) is that traditionally SONGS were sung unaccompamied and
Instruments were only used for Dance Music,except in Church, or in the
more upper class environments.It is only in recent times that some
sort of accompaniment has been considered neccessary for songs.
Bearing this in mind, the use of ANY instrument to accompany a 'Folk
Song' has GOT to be superflous, wether the instrument be 'acoustic' or 'electric.So we are back to definitrions of 'What is Folk',or a hell of a variety of personal tastes, which is where I am!
A lot of 'Traddy' songs do NOT work with accompaniment unless the guy playing the instrumnent is a bit Shit Hot,with a very good ear
for ALL the nuances, or has rehearsed exstensively with the singer.
By the same token a lot of contemporary songs lose a lot of their significance if sung unnaccompanied unless the singer has a rare
talemt for the materiel.
This seems to indicate to me that a song can be done a cappella or with any thing up to a full orchestra and it is entirely subjective
wether this is 'Folk' or not. Hence the 'acoustic/electric'argument
is totally superfluous.