As difficult and complicated as this subject is, it is also very simple. Please forgive the wordiness...
I have heard many similar concerns from "some" locals when they first learned I was flying my quad.
"This drone hovers right outside my kitchen window and spies on me... It does it all the time!"
And they have asked me what they can do. I have responded in much the same manner as others in this thread suggest.
Photos are incredibly important! (No offense intended)
Did it REALLY land? Are there photos to document this? Are we taking the word of someone who is overly paranoid?
And who are we to suspect someone is not relaying a legitimate concern?
Not to discount the concern.. I know it is real.
Not to digress, but it is important to point out that:
I think to some degree some are sending signals of distrust and anxiety relating to drones..
In other words, I suspect some situation(s) I have heard about are, or may actually be hypothetical. After some friendly education and communication the concerns seem to go away. In fact, a couple of those most highly concerned have actually asked me to photograph their properties and gardens..
If a sUAS were to fly and linger above my property, that is one thing. Frankly I would first think it is more likely the pilot is doing a photo shoot of another property nearby and chooses the vantage point above my space to do it.
If it were to actually "land" in my space multiple times in a day, I would "ground it" (blanket is a good idea) and document it with photos, etc.
Look for a license. Report it to the authorities, etc. But in the time that takes, it could lead to a confrontation. If one were to "ground a drone" it is likely an unhappy pilot may show up and need to be dealt with.
In my case (with one law enforcement officer per 160 sq mi.) I am willing and capable of doing just that. Make the call first.. Wait for the operator and sort it out. More often than not I suspect an inexperienced pilot is doing the wrong thing.. This can be corrected.
If it weren't licensed, or at least not marked correctly, it is time for education. Discover the motivations whilst recording the encounter, etc. Educate.
A property owner can ask us NOT to fly over his/her property after a first flyover.. And I respect that.. although, I have never encountered that kind of resistance. BUT one would have to know who/where the pilot is to make a case.
As stated in this thread, there are JERKS out there that ignore the law, or just don't know it.. and have essentially no clue or respect for others. They will make it more difficult for all of us to do what we do for a living and for recreation.
Always, always protect Family and friends. Obey the law(s) educate, and fly with respect. Fly safe.
My 2 cents.