The physicist Erwin Schrodinger, to illustrate an argument about quantum superposition, conceived the idea of a cat inside a sealed box with a small quantity of radioactive material and a Geiger counter which if triggered would cause a hammer to break a glass phial of hydrocyanic acid leading to the poisoning of the cat. If, as had been argued, quantum particles remain in a dual, indeterminate state until observed, then by implication the cat can be considered also to be in an indeterminate state - effectively both dead and alive at the same time.
When my brother's mother-in-law, Winnie, celebrated her 100th birthday last year, it came to me that the record of her as a twenty-year-old woman in the 1939 register would now be opened up from its 100 year closure. Winnie was very much still alive, but in the eyes of The National Archives and of Findmypast, she was, from their point of view, deceased. Like Schrodinger's cat, Winnie had achieved the distinction of being simultaneously both dead and alive.
Shortly before Winnie was born, there were only around 125 centenarians named in the 1911 census of the United Kingdom and assurances as to the information remaining confidential for 100 years might not have been seen as unreasonable. However, by 2018, the number had risen to 13,170 and, since longevity is expected to increase further, this number may only be expected to rise further. This raises the question whether a 100 year closure is any longer appropriate. Should we be looking at increasing closure to 110 years from date of birth?
This is perhaps more than just an interesting academic point. No family historian I have met would call for longer closure periods. There is constant pressure for closure to be reduced rather than extended. However, centenarians may have the same embarrassing family issues buried in their past as younger people, should they be better protected?