Andy - it seems to me that the trio were 'booked' to play a three song spot. They turned up in plenty of time, played their spot as agreed, and went, having fulfilled their booking. Where's the breach of etiquette?.

Let's forget kids for a moment: if I knew a top performer was around and he/she gave his/her time to support a session with a brief performance, I would be grateful, not resentful.

Stu