I guess that's why it's been practice for the past few thousand years; because it's so ineffective.But, again, the most unrelaible way to gather information it through torture. Torture is much more effective at getting confessions. Even the innocent will confess. If you want information, you use more effective methods.
Any information, regardless of the collection technique, has to be varified. That's the difference between, "raw intel", and, "actionable intel".