Do you have statistics for both? To me, it looks like the reduction of crime is backed by some tentative numbers, whereas even organizations explicitly dedicated to finding violations of privacy report a a small collection of anecdotes.

Not to mention that as far as I am concerned, even someone e.g. breaking into a house - not speaking of violent crime - is far more damaging and traumatizing than some random cop looking up his exes license plate and doing nothing with it. Even if the numbers of instances were comparable.