I think it's safe to say that drones are not going to be shot down over a city without drawing a lot of unwanted attention. You don't commonly see people out shooting in public, and those very few who do are quickly dealt with. There is also an impractical side to shooting them down, you'd need to know the flight paths and schedules and then camp the flight path if there is no set schedule. Someone is going to report a man sitting on his porch with a shotgun, at least in Canada anyway. As another poster pointed out, it's just posturing for anyone to say they are going to shoot down the drones. Before anyone counters about shooting them down out in the countryside, it would be impractical and I don't think Amazon will use drones for rural delivery.