Bunny you appear to have completely missed the points I was making:
1) there is a difference in style between singing with or without instruments, just as there is a difference in style of playing instruments without the restrictions of accompanying a singer
2) different types of song invite/expect different levels of (singing) participation, e.g. songs with a chorus or refrain, ballad or shanty 3) far from it being due to overinflated self importance, there is recognition that a singer can be so thrown by someone's joining in where they are not expected that the singer may find it difficult to carry on with the song at all . (Joan Byaz and her amp may be unfazed but not everyone is that confident and I wonder how she would feel about a fiddle playing a slightly different tune louder than she was singing!)
Finally as I said in my previous post, appreciation and manners - appreciation of what is apt, and manners to only join in where apt. Jude - who intends to get suitably drunk and thoroughly enjoy lots of chorus songs at Towersey on Thursday.