But there is one thing that Mr Bezos and his putative drone fleet don't need to worry about. That's irate gun owners beneath their flight path shooting the aircraft out of the sky.
These days it's standard: some drone story or other goes large - police, Feds, Amazon, whatever. The next day in gun-heavy states, the local reporters look up some reliable gun firebrand, who reliably states that the first time he sees a damn drone above his property, out will come his trusty duck gun and blam - no more drone.
Except that's no more credible than the sky-fulla-drones idea in the first place.
Our man with the shotgun is not much up on drones, of course, and the reporter is not much up on guns or probably drones either. But if either knew a few basic facts about both, he would see that trying to shoot down drones with any weapon a normal American might have about the house is a non-starter.
Our shotgun-owning American is fairly likely to be a duck or other wildfowl hunter, though, so he would admit that hitting and bringing down a flying bird isn't likely much beyond 40 yards slant range using modern steel shot, or much beyond 50 no matter what using any kind of shotgun ammo*.
A quadcopter is on the same rough speed and size scale as a wildfowl, and rather less vulnerable if anything: most can keep flying having lost a rotor disc, while a bird can't keep going having lost one wing.
And, crucially, a quadcopter has no reason whatever not to be flying at least 300 feet above the ground for almost all of its journey, most probably much more: well out of practical shotgun range.
And our gun-fancying US resident would not, of course, claim in public that he could hit fast moving flying targets (other than by fluke) using his rifle - because his mates would laugh at him. Shotguns can knock down birds (or drones, maybe) within 40 yards because they throw a "pattern" or cloud of projectiles some of which may hit the target despite the difficulty of the task. Rifle bullets remain effective over much longer distances, but hitting a small fast-moving faraway target with a single bullet isn't practical and nobody even tries.
In a military context you might hit and cripple something very large, pretty close and relatively slow - like a manned helicopter landing or taking off, maybe - by firing rifle bullets rapidly at it out of a machine gun and adjusting the tracers onto target. Mostly you'd rather have a heat-seeking missile or full-blown antiaircraft cannon even for that sort of job.
Even in the States, a weapon that can shoot full-fat rifle bullets (as opposed to more common and considerably less ballistically potent intermediate-power rounds such as 5.56mm) on full auto - sustainably, without the barrel melting, remember - is not simply obtained. Even in the US, tough-talking fellows who have managed to get hold of such a gun may not have backyards isolated enough that they can safely start loosing off full-power rifle ammo into the sky without upsetting the neighbours and/or Feds, cops etc. The bullets will be coming down miles away.
And of course if you do have such a backyard, drones will not be able to reach it to fly over it anyway.