The idea is that if they cut out all the extracurricular / social aspects of a child's life, then the child will have nothing better to do other than focusing on academia. Of course, in reality that doesn't happen. Children will rebel when they come to that age.

As for the no violin / piano. I think you have it wrong. It's "no musical instruments other than piano or violin." (http://articles.chicagotribune.com/2011-03-06/news/ct-met-ti...)

"Never allowed to: - play any instrument other than the piano or violin - not play the piano or violin.”

you read it wrong.

Folks, the list is supposed to be funny. Of course it's over the top and somewhat arbitrary. The author knows it. She's also over the top and somewhat arbitrary.

I think the phrase is "ha ha only serious".

It's intended as a somewhat humorous wording of "you MUST play an instrument; your choices are piano or violin, NOTHING ELSE."