During a game today in Sweden's HockeyTrean, the 5th tier of Swedish Hockey, a player struck a referee when he was not looking. This resulted in the referee breaking his arm, and lying injured on the ice for several minutes.
In the video, a player dumps the puck in but bails out of the corner, and as the defensemen pivoted to go after the puck, he lays a massive hit on the referee. The hit looks pretty intentional from the video, however, there is some plausibility to the claim that he didn't intentionally hit the ref, and thought it was the player.
The player responded to the media after the game, saying that it was an accident that he hit the referee. However, he does go on to say that the referee was in the way the entire game and that he had to follow through on the hit as he thought it was the opposing player.
Hopefully, the referee will make a speedy recovery and will continue to referee games in the future, as hockey is in dire need of their services.