Because the news don't always give the correct facts or much of them, I highly doubt it has it's own capability to friend/foe identify, let alone shoot by itself. Unless it's wartime or strictly enforced that life fire automated weapons will show no mercy in "x area"
Just like UAVs, manned hardware or ground forces, you generally need clearance to shoot unless certain parameters are met, like being shot at yourself.
I can't see it ever shooting a civilian, these will no doubt be manned 24/7 or at least to the capacity that if it detects anything, someone, somewhere will be notified and ready to issue the right commands.