If your child is invited to attend the pantomime with their school mates. Ticket paid for. Children to be driven there and supervised by staff who volunteer to do so. Returning to school at 9pm.
You say 'thanks' don't you?
Or even 'sorry can't make it'.
Not 'I won't be available to pick up X at 9pm. Please will a member of staff wait with her until 9.45 when I will be able to get there'.