Cheering at a play is not debatable when the producers, who worked for weeks on end, ask the audience to please not disturb in the middle.
Every mother tries to instill middos tovos and chessed in her girls. But even more important is teaching them derech eretz.
If the girls were approached by their principals to stop cheering and they didn’t, it can only be called a gross lack of derech eretz. And it doesn’t get excused by the fact that they love to do chessed.
[Rebbetzin] Chumi Tauber