MistressDeeCee, the reply listing all of the stuff teachers pay out for was not to the OP, but to the poster who stated that dance teachers should not ask for volunteers but should pay everyone for their help towards shows etc because they are 'minted' (in their words).
The child I turned away from Acro - this is the 6th week of term and she has been 15/20 mins late every week, parent normally drops and runs. It's in our T & C that students must attend the warm up part of the acro class, and it is not fair for the other children to then have to repeat it (she is too young to do her own warm up at the side). It simply isn't acceptable to walk into the studio and start with the cartwheel / handstand / bridge part of the acro class and there is a real risk of injury. I am a little less pedantic about lateness to other classes unless it becomes a regular occurrence, but I can see why the teacher of the OP's daughter was a bit fed up, 2 weeks before a show and they are probably utilising every moment of class time. ( and especially if the girls walked in announcing that they were late because they had been to Nandos as opposed to something unavoidable such as a traffic holdup).
I fully appreciate that parents work etc, and I have often looked after children whose parents have been running late after class, or had them drop their child off quite a bit early because they are juggling various things, and supervised the child in the studio whilst teaching another class. As paying customers they deserve a high standard of tuition (which I hope I am providing!) but their right as a paying customer to turn up when suits them as opposed to the time that the class is due to start, does not trump the right of all of the other paying customers in that class to a full uninterrupted lesson. Therefore I would rather turn away someone who is habitually late and refund their fees for that session than have classes disrupted regularly by their late arrival. Unavoidable occasional lateness I don't have a problem with, but from what I understand from the original post, the lateness could have been avoided if they had opted for somewhere with quicker food service than Nandos.
I think Backforgood has a good point that the teacher may well have been setting a routine, and having to repeat choreography for a late arrival is frustrating for both the teacher and other students.