[spacebanana7]

The possession of power and the misuse of power are of course different things.

But knowledge of the full population is particularly corrosive kind of power. It can reveal negative information - one can query for all people without a donation to political party, for example.

[jiggawatts]

Only if that data is in the same table.

The primary key is just a number, and tells you nothing other than perhaps roughly when you were born (if it is sequentially allocated).