edit: Good point, I agree that parallel construction is an important concern, especially since there's so little transparency in police investigations. One possible solution is to force them to limit the duration recorded to only a few seconds. (I previously thought that's how ShotSpotter worked. Turns out they've kept days of audio before, apparently for "debugging purposes.")

> Drug crime is known to be fairly evenly distributed across different incomes, arrests are extremely biased.

Keep in mind that the reverse is true for gun crime, where low-income minority communities suffer from the lowest clearance rates.