Absolutely right about the subpoena part, having gone through that and ALMOST having to make it public information to the court because I was at one time a part of a court case that was dismissed (thank God!). My T was very blunt about what he would and wouldn't share with the court though. He could legally deny them access to certain material and force the other side to petition the court citing irrelevance etc., which he was prepared to do. Thankfully I never found out what would have happened!!!
Your right--- HIPAA sucks. I'm not a fan. Our laws don't do much for us in some situations. That's why it's so important to have a really good T.