Hmm... let's re-word that a bit and see how you feel from the other side:
Flying a drone in a populated area is unsafe in nearly every circumstance. Just because there's no malfunction doesn't mean there couldn't be. If the done had suddenly dropped altitude, would the pilot have tracked it like a skilled operator to land it? Would that have brought the craft down to a point where the pilot could have endangered neighbors? What if the drone landed in the pool? Was the pilot certain that in all cases his flight-range was clear before flying? These are all things which a responsible drone owner thinks about.
I hope the pilot gets a big-ass fine (I'd hate to pay for his jail food out of taxes). I also hope the flier gets a fine for trespassing - or even just gets called into court and let of with a warning. The lawyers fees will probably be 10x what the drone cost to begin with.