My home clubs require written permission for flying them on property and to take photos. To my knowledge it has only been authorized for publicity (ex website flyovers) and no one has violated that stance. Now if a drone is piloted over the course by someone off property, we can notify authorities because it is a violation of privacy (drone pilots do have regulations to adhere to).
As far as architecture, I find no more knowledge can be gained than a helicopter flying overhead except for more ground level video. I don't see it impacting design philosophies though there is just as much of a possibility of positive impact as there is negative impact.
cup half full or half empty philosophy - its all in perspective.
Also, it is not too late if someone pulls up and takes a drone out on the course. The course can absolutely deny the use. Public or private course, you are still entering private property just like walking into a theme park. All facilities have the right to refuse the use of certain devices and can penalize how they see fit.
I do not own a drone nor do I foresee myself buying one. Do I like the photos? Yes sometimes. It gives an interesting perspective and I enjoy the vantage point. They can be an effective marketing tool and entice people to play a particular course. This was the case with a flyover tour I saw of the Hideaway in Palm Springs. I had never played the courses so I used reciprocal playing privileges to play there after seeing some aerial photos. I do want them to be piloted responsibly and like with anything else, there will be idiots who are reckless and have a total disregard for public safety and privacy. That's just human nature.