We checked this out, and it's legit. There's a video from Friday of someone throwing a paper airplane from the cheap seats at a soccer stadium in England. Which then glided the whole way down . . . and hit a player in the back of the HEAD.
The crowd went NUTS when it happened, because England was playing Peru, and it was one of the opposing players. There's also a photo of him right after he got nailed, and he looks totally caught off guard. He was fine though.