1. The music teacher is a specialist, probably teaches every child only once a week, unlikely to know parents. 2. Good for the school, conscientious checking child's safety. It is unusual for a 7 year old to enter a school alone. 3. Bazar! Must have been some kind of misunderstanding? Kids not picked up usually goto the reception. Schools are usually super hot on this stuff as it's safeguarding. Hope that gives you the feedback you need. I will add that's it probably best to take this to the school rather than a public forum.