Boy, does this hit home. As an a cappella singer, I know first hand what the poor singer went through.

I can play several instruments... but poorly, so I do not inflict my playing on others. My true instrument is my voice, and I am quite capable of doing justice to a fine old aire, ballad or shanty. But I find that here in the USA, as you saw over on your side of the puddle, folks with an instrument tend to domineer sessions and what are called "sing-arounds"( but tend not to be so in practice).

And many of these individuals are just not capable of actually accompanying the singer, but rather play in whatever key they can regardless of what key is actually being sung. So, while they may be able to play an instrument, I don't regard them as accomplished musicians. Especially because they are ignoring the "music of the performance", for want of a better term.

And what often happens is that good singers get tired of having to "fight the crowd" just to get equal time and just stop attempting a song or even attending. And that's a loss to everyone.

I guess the only way to ensure good etiquette at these gatherings is to have a set of ground rules and then enforce them. Relying on the curtesy of others doesn't seem to be very effective... which is a real shame.

Sorry for venting, but like I said... this really hit a nerve.