When such people is in 100m range from event - nothing can be done Police forces _has_ to act before such happens This is like metal detectors in airports - u

When such people is in 100m range from event - nothing can be done Police forces _has_ to act before such happens This is like metal detectors in airports - useless Coz if someone want to do harm - they can do this on parking, in line or in any areas near where people are crowded And even more There is no evidence that facial recognition lower terrorists attack possibility