In North Dakota, at least, it's now legal for police to fly drones armed with tasers, tear gas, rubber bullet-shooting weapons, or anything else that qualifies as non-lethal. It was only a matter of time; they've been flying them with cameras for some time now because the drones can hover high enough that they can't be seen nor heard, yet transmit "intelligence video" in real-time. Obviously, they were going to want to take the next step.
Not too long ago, Lefties would tell you that Walmart had a sale on tin-foil when you mentioned this possibility. Today, it's a reality.
If you're on your own property, you're supposed to have a reasonable expectation of privacy. Forget about that.