After reading this whole thread, a couple of points:
A hovering drone would be easy to drop with a .22 rifle
My neighbor, who is a professional, has a drone that carries a full sized 35mm digital SLR camera. Resolution could easily be in the 50 megapixel range. It has gyroscopic image stabilization and can carry a moderate zoom lens. The point being, it can take super sharp hi res pictures.
His drone is very large and very loud. You can hear it over the TV, windows closed.
As far as photography laws, in general it is legal to photograph anything that is visible from your property or public property. That includes you in your speedo if you're in an unfenced front yard or even in your living room if the curtains are open. Certainly different states may have different laws, I'm just speaking generally (as a photographer). Drone law is going to have to better define what is the drone operator's property (air space), public property (air space) and private property (air space).
The other thing to think about as you fire on an intrusive drone is that it is possible, even likely, that they have live video feed. That means the pilot may have a record of you fancy shooting.
And yet, if one was hovering over my rural property in an intrusive way he would get, at the very least, a "shot across the bow".