With 8 stitches in my hand, not more than 12 hours ago. I have just gained new respect for multirotors, they are powerful beast.
I really really hope that Amazon puts proper protection in them drones so there are no injuries. The little toy one I have spins at around 5000 rpm with rotors with 16 inches propellers. It can cause serious injuries, just ask my hand.
Who will be responsible if an injury does occur, which they will. If you look at the Amazon prime air demo, the customer asks the drone to descend via his smartphone. Say there is a 5 year old standing under this thing or comes running in its direction, are there smarts in the drone to abort the mission. Who is responsible for the injury, Amazon or the customer who sent the descend order?