Jim.
I understand that if clubs have policies and they are clearly stated, then people are free to make their own decision to attend or not.
I am not sure that you are right about this
"Some Irish clubs (it doesn't have a folk-club scene) adopt a no-instrument policy because that's the way the singing tradition here works best,"
my personal opinion is that this is incorrect,Ilike the occasional variety of an accompanied vocal when performed well, but I respect clubs policies and am happy to go along with it, in fact i find it a challenge to try and present a night of unaccompanied singing.
do you mind explaining why you think the IRISH singing tradition works best with a no instrument policy.