Right, if you flip a hundred coins, about half of them land heads and the other half tails. The correct coins we'll call oracles, and the incorrect ones liars.
Now you perform a hdd recovery that is successful 70% of the time. That is still worse than the performance of the oracle coins which were correct, and if you invert the performance of the liars, they also beat the performance of the recovery.
If you have two coins, one which is always correct and one which is always incorrect, you can flip one of them to decide whether the other one is correct (and pick the opposite).
Check mate, statisticians!