Where I live there are several dance schools and one in particular has about 500 students at least but the majority of them are not allowed to take part in shows. The principal opened another school branch for festival work which was just for the chosen few who were good enough to get into JAs and would win at completions etc. She then never looked in on the other children at the original school. My friend whose child was at this school complained that they would be asked to contribute money for the festival girls to pay for their transport to competitions!
I am not sure how widespread this sort of thing is? At your dc's dance schools how inclusive is it? I think it must be disheartening for a child who feels they are just making up the numbers.