It seems to me that the key to this is being sensitive to the context and to what is appropriate behaviour for that particular event and occasion. There is a huge range of types of events and environments in which our music is performed. What is OK in a singaround or session may not be appropriate in a concert. At a concert in a festival tent one might expect people to move around, whereas in a concert-hall it might be reasonable to expect them to be more attentive - or they might be dancing in the aisles. Also, some clubs and singarounds have their own culture of what is and is not acceptable.

Some events offer opportunities for novice singers to learn and develop their skills, or even for those who are clearly never going to improve. At other events, it may be appropriate to overlook them in favour of better performers.

It can be wonderful to be in a singaround or a session and hear fantastic things developing as people spark ideas off each other. But it is also wonderful to be spellbound by a great singer as they deliver a ballad solo.

In some circumstances it might be egotistical, as Richard suggests, to insist that everyone else shuts up while you sing. In other circumstances it will be egotistical to join in.