The recently announced DJI Phantom 4 Drone is finally pushing obstacle avoidance technology to the point where you are no longer worried about hitting trees, people or god forbid birds other flying craft. There is technology here that just 5 years ago would have been extremely expensive, however don’t expect this self awareness of space to translate into a perfect set and forget technology for now.
There is a lot of improvement here and the mobile application lets you track subjects and paths with just touch and drag. There are things that drone makers like DJI are working behind the scenes to get obstacle avoidance and self awareness even further to a level where people and governments can relax about these craft being a danger to society. We are still not there but things will continue to improve along those lines.