"Without hazard" is pretty subjective, but I agree that it probably shouldn't include casually flying around cranes.
I don't know how drones are programmed, but landing immediately if the battery gets low certainly sounds like a sensible precaution. Electric motors might be reliable enough that you don't have to worry about gracefully handling failure of those. I hope so, because I don't think a quadcopter has much hope if any motor fails.
I don't know how drones are programmed, but landing immediately if the battery gets low certainly sounds like a sensible precaution. Electric motors might be reliable enough that you don't have to worry about gracefully handling failure of those. I hope so, because I don't think a quadcopter has much hope if any motor fails.