In some countries maybe, but in west where all the valuable infrastructure is there is absolutely no way you could get a permit to shoot down anything.
Obviously your biggest customers would be in active warzones, or areas worried about soon becoming warzones.
Drone attacks on US soil are (hopefully!) not happening anytime soon.
believe it or not but legislation can change pretty quickly when shit actually hits the fan
Given how quickly this technology is proliferating I think that could change. Numerous non-state groups are using drones offensively in Africa and Colombia. If a drone hit something like a refinery and there was significant impact, don't you think the status quo could change quickly?