Historically, the ease of access of records and court approval came in business cases. But that body of law has been transplanted with little thought to personal, medical and financial records.
Texas' law is among the narrowest in the country in defining insanity.
It's very possible that their phone conversations were intercepted under this program that we are just finding out about.
This is just the latest attempt to put a dent in the execution industry and it will take a while to play itself out.
Generally speaking, to do that the government needs a warrant based on probable cause.