Mythbusters more or less proved the consumer models are basically harmless to humans and couldn't break the skin.
As always something new comes along and people are terrified. It's our stupid nature.
A commercial quadcopter motor typically runs at 1000KV, meaning that it spins at 1000 RPM per Volt. Most batteries are 12-14 volts.
Even for little plastic bits, if they're spinning at 12,000RPM, theres a lot of kinetic energy behind them.
I'll admit I was surprised to see that, indeed, they were able to puncture through that poor soul's ballistic gel neck and sever the "aorta."
0: http://www.discovery.com/tv-shows/mythbusters/videos/drone-d...
(A secondary issue would be a drone getting sucked into plane's engine intake. I don't know if it would break the engine, but it would definitely take away some of it's extremely expensive life time.)
As for us pedestrians, a cheap drone with plastic rotor blades (it's a different with carbon fiber; I've heard of cases where old-school RC helicopters chopped off fingers) may not damage me on impact, but getting near-missed by a fast-moving, loud and non-ballistic object can freak one out, making one drop stuff they're carrying, fall off one's bike or run into traffic. And speaking of traffic, I wouldn't want to see what happens when you distract a driver with a drone on a busy road.
It still doesn't solve the problem of cheap drones (i.e. those without GPS), though I'm not sure if they are an issue near airports.
Not only about rogue individuals launching programmable drones to do malicious things, with no accountability (first time robots would be out in public with access to so many people)
But also just simple failure rates and gravity
Do you foresee the skies blackened by Drones? All these issues have existed in RC planes for years and I'd say they're only slightly more common.
RC planes are remote controlled at least. This is the first time we have autonomous robots among humans.
They only "proved" it couldn't break the skin. They didn't prove it was harmless... if one slams into your head, you're going to be on the ground.
Often the injury concerns come not from propeller blade cuts, but a lithium battery getting dropped on someone's head from 200ft when it loses charge unexpectedly.
I have a $50 UDI U818A and (with the plastic frame) if I cut the power, it falls no faster than a leaf. It actually does the same 'wobble' and lands softly on the ground.
Larger multicopters, like the DJI ones in the article, are much heavier. About 5lbs or so. They fall fast and hard.