The comment that mentioned parachutes was talking about how a drone crashed at an event and almost injured people. My personal homeowners liability policy covers things like hitting someone with a shopping cart in the grocery store and hurting them, it probably would also cover a drone, but if you don't have insurance it could expensive real quick.
The cool thing about sidewalks is that they are elevated and it takes some effort to hop on to one and run over pedestrians (especially when there is a protective lane of parked cars). Drones, on the other hand, are poised to fall on people, with no barriers.
In my case it didn't occur when I was flying the quadcopter but rather when I was bench testing the ESCs (yes, I knew abstractly I should remove the props before doing this but I got lazy after a while of testing and eventually it bit me).
Having said all of this I mostly agree with the grandparent post (though I do recognize that a 2 lbs drone could, theoretically, kill someone) in that the solution to this as a safety issue is primarily just don't fly a quadcopter over anything you wouldn't feel comfortable crashing it into (basically don't fly over people or valuable property it could potentially damage). As long as you stick by this rule of not flying over anything you're not afraid to crash it into you already have a good (if not inexpensive) failsafe, which is just cut the throttle completely.
And that seems like it's being pretty generous. In most "quadcopter crash" videos I've seen on YouTube the drone was much higher. Sometimes even hundreds of meters.
[1] http://diaryofnumbers.blogspot.com/2010/11/death-by-coconut....
If there were as many drones (of that size & rotor size) overhead as there are vehicles on the road, I'd still expect to have zero to single-digit fatalities from drones every single year--at least from "falling out of the sky onto people's bodies."
Perhaps there are more likely cases where the drone is the indirect cause, like breaking someone's windshield and causing a fatal car accident.
Am I okay with my new born infant's soft little squishy skull living in a world with drones, which occasionally drop out of the sky?
Yep.
And we do live in that world, actually. They've already been "introduced," as you put it.
Already been introduced(bad term)? So 1 in 3 households have a drone in the U.S.? OK 1 in 4? You can always count on this statistic- 1 in 10? Nah? Surely 5% of Americans own or use the services of a drone then right? Yeah then they haven't been introduced yet
They're so small I doubt they'd have much of an impact on light aircraft either.
For the large bird test, the engine is allowed to shutdown.
The energy we are talking about is not insignificant. I'm actually in favor of allowing people to fly drones with as little restriction as possible but let's not pretend there aren't some risks.
In any event, it takes a person 8s to get close to terminal velocity — that's a drop of 300m or so.
The energy involved is certainly non trivial but energy is not the whole story. The densest, heaviest pieces will be the battery and motors.
Too lazy to do the calculations :P