> concept of storing PB's of easily searchable and accessible data
The scale of this dataset is probably on the two/three digit MB scale. It's 6.5 million people and everyone adds probably less than 500 bytes to the dataset.
Let's say it's 500 MB. This isn't "big data", but it's still highly sensitive. It's still "only" a file on your Computer and deleting it still doesn't delete it safely.
The issue is the effectivity of our data handling devices. As the file is so small, it fits onto current USB sticks cheaply. People can put those USB sticks anywhere and smuggle them out of their jobs. Snowden claims to have gotten the NSA data out this way and even if he lies, it's certainly a plausible method.
The more effective our data handling devices get, the more data can be leaked.
I'm a bit of a pessimist and think we won't be able to stop such leaks in every domain. They'll just get worse and worse over time, the larger the data sets get that are being accumulated about people.
Former Google CEO Schmidt has famously said that there won't be privacy in the future. Maybe he's right. Maybe he's wrong and we figure out a way to preserve it. But doing that is super hard.
Maybe society is just ever changing and the "stable" state will be some form of singularity where a concept like "living on a planet" is regarded as outdated because we live in emulated environments in free orbit around a sun and the planets are better off being dismantled to build more emulated environments, and all our thoughts, dreams, plans, our entire existence is accessible to the environment's operators who claim to be "fair" like Google, Twitter or Facebook claim today.