Good point about false positives. The device could upload images to a human operator who would activate the defenses. This would add some reaction time, but it would reduce the potential for false positives.
If the device has image recognition to detect firearms being brandished, the operator could trigger the defenses before the first shot is fired perhaps.
If the device has image recognition to detect firearms being brandished, the operator could trigger the defenses before the first shot is fired perhaps.