Cops are lazy and dumb as well. They use flock to find people in the area and accuse them of crimes they didn't commit.
They also find and accuse people of crimes they didn’t commit without using Flock.
They also use Flock to skip accusing people who they might have suspected if it weren’t for Flock evidence that exonerates them.
It seems like any meaningful analysis needs to consider the rates of all four combinations of {true|false} {accusations|exonerations}, and compare that matrix to the matrix for the status quo techniques.