Physicians are bound by both a professional duty and oath as well as legal liability to keep your medical information in the strictest of confidence. But it is nearly impossible to know in advance when a particular piece of medical information will become important for the treatment of a patient. Hiding it because of concerns about insurance or employment is not a solution--it's an indication that insurance and employment have undue influence on or access to a professional record.
Your medical record is meant to be a confidential record read only by those who are sworn to care for and protect you, and by nobody else for no other purpose.
As a student doctor it's alarming to think that people do not feel they can trust their doctor with their medical history. I wonder if this is particularly a problem with the US healthcare system.
Despite all of the kabuki theater about HIPAA and black covers on clipboards and whatnot, every single medical fact that is even considered for payment by an insurance company gets hoovered up into various industry databases and shared with any insurer who bothers to ask.
I think there's a big difference between third parties interfering with those notes for some profit motive, and the person who those notes are about interfering for privacy reasons, no matter how misguided.