I can't believe that everyone has had their full say on this.
In our neighbourhood it seems that singing without an accompanying instrument is viewed as abnormal and downright freakish, or ancient and boring. Certainly for concert-type folk venues. However, at one song session I used to go to, now alas defunct, the silence that fell in the pub for any (reasonably competent and accurately pitched) solo unaccompanied singer was striking. Maybe said session now defunct cos nattering and eating brings in more dosh for landlord? Oh, the trials of modern life.
Have noticed so many cases where earnest guitarist forgets to sing beyond his fretboard. Think of the SONG, not the blighted instrument!! Aaargh!