Sadly, the way things are now with terrorism, I would as well go along with metal detectors for entering all crowded areas such as airports, malls, court buildings etc.
The immediate emphasis would seem to be a punk-detector.
Maybe it’s coming to the place where everyone arrested would need to get a small implant that could be used to screen them from entering public places.
Metal detectors in unprotected gun-free zones create killing zones like at the airport. No police around to stop the shooter, everyone else disarmed.