Does anyone know why this isn't standard?
I Googled this question: "why don't quadcopters have safety cages" https://www.google.com/search?q=why+don't+quadcopters+have+s... ...
... and even saw cages that go around the whole quadcopter (not just the propellers as I was expecting). If those were a bit squishy they could seriously reduce any chance of concussion/property damage if landing on someone or something!
The YouTube video below is pretty amazing, it shows someone demonstrating such a cage.
"Spherical Cage Incased Quadcopter" - https://www.youtube.com/watch?v=5B3X6EvZ2XM
I've submitted it as a separate submission. (It's only 2 minutes.) He says it flies great, and he even seems to purposefully drop it several times from as high as the height of a building.
Also for anyone who hasn't been around drones much, in the middle of the video you can hear the annoying whirring noise people mention throughout this thread.