Being a Mama, I'm with Yerusalyim and Mulan on this.
Communication is all good and well, however, even good, well-adjusted, teenagers usually don't confide everything to their parents. Especially, if they would disapprove.
However, I don't believe in raiding a kids room and reading a diary for no good reason. I also don't believe that a kid has a "right" to privacy. Especially, when I'm footin the bill and ultimately responsible for their behavior. If I suspect there is a problem, and I'm not getting anywhere with my child, I'ma snoopin. That maybe the only way I can get info to help them. Which would be MY goal by the way.
As far as the JC. I'm getting a sick feeling in my stomach. My heart goes out to your sister. How convenient for your parents to be able to pass off their parenting responsibilities to the elders.
Andee