Drone Liability Insurance
It is likely that in the event of accepting a request or commission to film using a drone, even for a private undertaking Liability insurance may be required.
At first thought it seemed that this would be a limiting factor if you wanted to embark on the business of providing a service in this regard. I would have to research this futher but seem to be many companies that offer this insurance. I will add a few links as I look at their offerings. At the present time I have no interest in this area.