You are right there is usually the 7 year rule that applies especially to such confidential information. But even just the fact if a doctor could see a patient had not seen anyone in 7 years alarm bells would ring. It's a shame that the 7 year rule doesn't then trigger some warning bells. But then... What doctors or bankers have time for that? It's not their job.. Its just such a shame that while we should not have to live in a surveillance state that there are some indicators if records could be used that could actually help to alert something being amiss. If Sally had been taken seriously straight away, there could have been so much documentation to draw on that has since been destroyed.
The thing is, Sally was taken seriously straight away. It was the initial investigation that uncovered the account at the Colonial Bank in Ashmore- Sally didn't know about it. Marion was identified there withdrawing the balance of her account. Jack Wilson, in his letter to the Salvation Army, said that police told him "Bank security had contacted her on the phone. He said that the bank security were like police, and they were satisfied with their investigation, and that if I wanted to probe further I should get a private detective and start in Byron Bay." Episode 4, 7:12
In the letter from the Salvos, it was stated that his (Jack's) daughter had been identified withdrawing money at a different bank (we now know to be the colonial) and that she spoke of starting a new life. Episode 4, 8:12.
Actual police protocol states that a person in authority, not a police officer, needs to sight the person who has been reported missing.
A MP must only be ‘located’ when he / she has been sighted by a person in authority (eg: Police Officer, Customs Officer, Family and Community Services, Department of Immigration Multicultural and Indigenous Affairs, Department of Corrective Services, treating Doctor, Mental Health Practitioner, School Principal). If in doubt seek advice from the MPU. The locating officer should sight the MP and check that the MP is safe and well and provide any assistance where necessary.
https://www.police.nsw.gov.au/__data/assets/pdf_file/0014/631004/nsw_police_force_handbook.pdf pg 186
I asked, and yes, a bank employee following correct procedures would be a person in authority. So, a bank employee, as a person in authority, identified Marion withdrawing the balance of her account from the Colonial bank in Ashmore. They were able to follow up via phone call, with Marion- so they had a number. It seems this phone call is where the "tell Sally I'm angry about the car, and tell them to stop looking for me in Byron Bay" came from. She was deemed located, and therefore this would have been a closed case, and, as described in the podcast, would have been destroyed after 6 years.
For all we know, the police do have information about Marion's movements after 1998. Marion had said she wanted no contact, therefore Sally is legally not entitled to this information. If Marion walked into a police station today, and said here I am, here is proof, I want no information shared, not even the location of the police station, then that is all Sally would be entitled to.