So I am a drone pilot in Colorado with a Part 107. I am hoping to start selling drone footage on websites like shutterstock in order to make some money on the side. I was wondering what are the main legal issues with selling drone footage as stock footage? I know that you should not sell footage where you can recognize specific people or properties without their permission but are there legal issues with general urban aerial shots, as getting the permission of hundreds of property owners would not be realistic? What about public gatherings?