[chiph]

There have been photos published on Reddit from people who were seriously cut up by the spinning propeller blades - both from RC helicopters and commercial quadcopters.

Not something I want happening to me, or being responsible for.

[dirktheman]

Don't get me wrong, it's a great hobby! Designing, building, tinkering, flying, improving (and repairing, always repairing) your own models is very rewarding. If you know what you're doing it's not a very dangerous hobby, too. A lot more people get injured with baseball, american football, kayaking, paragliding, cycling, racing, scuba diving, boating just to name a few. If you have a little common sense (not grabbing your UAV out of the sky with your bare hands, for instance), keep a safe distance with buildings, roads, people and animals you'll be fine!