Net Gun would only work for low flying, slow speed ones (unless you have a huge net.) Same problem one would have with birdshot.
Other anti-drone/UAV tech is needed.
But how does one encourage the development of anti-drone technology. I assume various militaries are either trying to develop or have developed some technologies/strategies to combat drones (but are keeping them closely held until they need them (or I am over-estimating their foresight and intelligence.)
But also, in the case of drones being used by police states or just by public/commercial entities (invading privacy, etc) I would appreciate the development of defense methods accessible to the common person.
I can only guess based on theory and sci-fi, but I can't think of too many different avenues for defense against drones. One is just stealth/camouflage, but I assume it is hard to hide from infrared or just an over abundance of cameras (especially if those cameras are hard to detect.) .So like while roofs would prevent basic cameras, thermal shielding of some sort would be needed for infrared or heat detecting ones. Plus, in the case of say a guerrilla war/rebellion/protest/revolution/etc mobility is an issue and big, roofed buildings are obvious to other means of detection.
One could target the control signal for controlled drones (hack the signal, disrupt it, replace it with your own) and either take over the drone or at least cause its failure. For autonomous ones, one would have to interfere with the signal transmitting the camera/detector feed, perhaps replace it with a false one. But I assume with the right precautions and encryption, these methods can be thwarted.
Physically targeting drones would be the most likely solution, and at first would probably be some sort of seeking missile or counter-drone, but there are plenty of problems with this. High flying drones, if they are even detected, would be hard targets. Furthermore, drone vs missile combat would probably resemble current anti-aircraft/SAM combat, and would require both a means of drone detection/targeting and high number of anti-drone weapons.
And as the technology improves, drones and their cameras are getting smaller and cheaper, and then it becomes a problem of numbers. If someone can deploy hundreds of cheap cameras, they only need one or a few to survive any counter-measures. Or they can become so small as to be virtually undetectable, or so numerous as to be ubiquitous, or taking the form of natural entities (birds, insects, etc.) and they can operate individual or as bot-swarms (each providing unique problems.) In this case, its becomes an arms race as measures and counter-measures and counter-counter-measures are developed.
Perhaps the best countermeasure on both large scale and the small/personal scale will be drones themselves. Eventually, large areas (countries, cities, estates) would be protected by a "dome" of numerous, replaceable, small defense drones (similar to the ones in Stephenson's The Diamond Age.) And then personal defense drones shadowing and protecting individuals or perhaps even clouds of defensive nano-tech. (like in plenty of sci-fi stories,)
But the development of countermeasures needs to be spurred on by necessity and needs both funding and technical means.
So I would suggest just constantly invading the privacy of the rich. Hovering over their pools and outdoor parties, peering in their windows. Either they will get lopsided laws written that only prevent poor, citizens from using drones (which is entirely a possibility,) or a market will appear spurring the development of measures to thwart drones. Of course this could spiral out of control in many, many ways, from just private, semi-sanctioned police/security forces "protecting" their clients, to a robot vs human war (where maybe EMPs would be helpful.)