Naughty corner... NOW!!!

I've recently commenced full time dance teaching. 30 hours a week ages varying from 4 years old to 18, and I have stumbled upon the fact that discipline is a fading value in this generation. As a little Ballerina growing up Miss Elizabeth (my teacher/principal of the school) was almost other worldly to me. I never dared to talk when she was talking and if she gave me a correction I worked so hard to perfect it that I could have burst.
These days it's going something more like this:

Miss Danika: "Chenaye stretch your knees in your grande battement"

Student: "I am"
Miss Danika: {demonstrating/ talking students through an exercise}
Entire Class {with back turned to Miss Danika} "chat chat chat giggle giggle giggle"

When did this happen? It upsets me a lot. Dancing (Ballet especially) is about grace, poise and discipline... apparently now it's grace, poise and obnoxious know it all's...
From this-

To this-