Seems a shame to bar someone from singing just because they don't have any one willing, able, available to play on the night.
Must be a drag for someone who's voice is their instrument to be censured for trying to make the most of it.
What's the POV on people who cant sing without a P.A?
Maybe if the excuse is that the audience is too large there should be a reduction in the size of the audience to allow a proper acoustic set to be played?
Lastly and even more tongue in cheek what does the 195? commandment have to say on the matter of folk and amplification/backing tapes etc?
If there is no opinion given maybe neither should be allowed.