One person.
Look at this another way: they successfully matched one (1) person for the duration of the trial. For a sample set of this size, that looks like a huge success.
What if that one person hadn't taken that route during the trial? Then they would have matched 0%.
Cynic in me asks: how much did they pay that one person to walk through the area so the test would look like a success? Did they just get lucky?
(And TBH the other comments above are right: even if it had only a 1% false positive rate, the real issue isn't accuracy here, it's rights.)