There are no federal laws prohibiting a drone from flying over personal property at this time just as long as it flys withing certain height limitations. While not new, drone technology is becoming more affordable thus you are seeing more & more hobbyists every year. As of right now, drone technology must adhere to federal and state "remote control vehicle laws". However, many states have ammended such laws to include drone use seeing as many businesses and emergency agencies hope to use drones for various reasons.
I am a drone owner & pilot. I own seven drones. Four are custom built for high velocity racing & aerial acrobatics. The other three are for training purposes. Drone racing is becoming very popular and you are likely to see a professional circuit sooner than later. I've also been approached by many real estate agencies looking to hire me & my pilots to record video of houses for sale & rental properties in order to produce virtual tours of their properties for website & social media use.
If the man who shot the drone down had lived in the country, chances are he would not have been arrested. However, there are various local laws & ordinances that regulate weapons fire, which it looks as though thats what he was arrested for. Most responsible drone owners would not trespass onto someone else's property without seeking permission first. Most drone owners custom build & drop a small fortune into their drones for various reasons, many drones being worth more than a used car, and they would never chance losing such an expensive piece of technology that they've put so much time into.
Like it or not, drones not only here to stay, theres a good chances that most of you will live to see the day when you encounter at least one drone on a daily basis.