In many places, medical records are closed in perpetuity for reasons of privacy. This means that even records that are, say, 150 or years old are closed to researchers. This makes no sense to me, and I've always thought there should be a provision in state laws that all government records will be open after a certain date. After all, what kind of harm can come from allowing historians and genealogists to look at records that are twice as old as human life expectancy?
On her blog, Paula Stuart-Warren highlights an example of heavy-handed use of privacy laws; in this case, HIPAA* being applied to the records of a Civil War soldier. (Via Midwestern Microhistory)
*HIPAA is the Health Insurance Portability and Accountability Act. Not to be confused with HIPA, the Hawaii Island Paddlesports Association. They bear no responsibility.