Funny thread,
Most people here have opinions and virtually no understanding of US law. Additionally, the logic used tends to reflect opinion of what they may prefer. How about answering the questions with facts.
Reasonable Expectation of Privacy, is not implied by putting up fences and being able to see thru, around or over top of. Additionally, windows are not a barrier to privacy. Your back yard may be private, but viewing it from a satellite, helicopter or drone doesn't change the expectation, just the capability. Their is no law that that says you can view a house from the window of aircraft but then says if you use a camera with a 400mm lens it becomes an invasion of privacy.
Invasion of privacy requires a unique action in which the invader seeks to hide, disguise, or otherwise conceal their activities while also gathering data, information, images (stimulation) or otherwise.
For example, software that is hidden from you that collect data, hiding a camera in a bathroom, hiding the crap in a Port-a-potty, recording a phone call are all examples of invading ones privacy on different levels. Privacy is not a constitutional right, many laws are created to protect privacy indirectly. I can photograph people at a park, but I cannot display images of children 14 and under on the web because of the Child Protection Act, I can't use the likeness of someone (images) for commercial purposes without a model release, or I am liable. But privacy is not technically protected.
As drones, pardon me but I like drones over UAS, become prolific they will become as common as CCTV cameras and will simply be apart of our expectation.
Perhaps a better question, and the one I bet will most likely be the real problem is property and trespass. The FAA has a difficult task of trying to declare their position that they own all airspace that is outdoors. U.S. vs Causby went to the Supreme Court and the old 83' foot rule technically didn't define who owns the airspace over your house. If the homeowner owns it, and you penetrate the boundary then you are trespassing. If the FAA owns it then you're you're not. By the way the FAA does not have jurisdiction on privacy. In fact everything they regulate is by default public.
Suffice to say, I can hover in your back yard and its legal. That's not say it wouldnt be frowned upon and cause a few problems but, the lower courts and case law up to this point would suggest that if the FAA declares all airspace public then it truely is and Oprah's backyard is no exception.