Comment by abentspoon

It's not enough to find 33 independent questions that evenly split the world's population.

An optimal, though inelegant solution to that goal might look something like this:

"Is the {1..33}th bit of sha1(name : location : date of birth) 1?".

Clearly you'll have tons of collisions with that solution, as you would have with any solution using 33 independent questions.

To uniquely identify people, we'd either need to use more bits, or look very closely at the population and derive very specific questions.