So much FUD here..
1. Drones != RC quadcopter or even UAV. Drones are unmanned military platforms. RC quads and UAV's are not - the human is in control. Even with APM doing waypoints, the human is still in the loop - just like cruise control or autoparking in your car still requires you to be the driver. Please stop calling them "drones".
2. Privacy. We do not need new privacy laws for RC quads etc, simply because they have a camera attached. Sticking a gopro on a broomhandle and filming your neighbour doing strange things with furniture and vasaline in his bedroom is already illegal in most countries. Attaching it to a RC quad does not make anymore more illegal.
3. Using a UAV or RC quad for commerical use is fine, but adding a camera does not make it so. RC quads used for agriculture, mapping, IR body heat detection (in collapsed buildings) etc, are all commercial and must be licenced, and you must be qualified to operate, and do all the paperwork. Whether it carries a camera or not is academical.
4. The farmer has a point - this RC was trespassing. End of. No point bleating about it. But lets not drag this into a debate about "drones", because that's a dark path. Both are at fault here, but unfortunately, the RC operator is the one who could be prosecuted - the video evidence was obtained "illegally" so the farmer is in the clear legally (though not morally). Just because it was obtained using a quad is irrelevant.