We have all seen it too many times: a hockey player swings his stick at the head of an opposing player, or attacks him from behind. This sort of violence is unnecessary in hockey (or any sport). The leagues sometimes discipline the offender, but are such acts also illegal?
The answer is that many of them are. The offender might be charged criminally, or, he might be sued civilly for any injuries suffered by the victim. Let's consider the potential criminal liability.
Canada's Criminal Code applies to every sporting event in Canada. The law of the country is not suspended just because the illegal act takes place in a hockey rink or on a playing field.
The most usual criminal charge arising out of a sporting event is assault. An assault is defined as any intentional application of force to another person without his or her consent. Given this definition, it would seem that every body-check in hockey or tackle in football is an assault. And they would be assaults if it were not for the "implied consent" of the victim.
If you are playing a contact sport, the law implies that you consent to a certain amount of rough play. At the very least, you consent to the body contact that the rules allow to tackle or body check, whatever is involved. You also consent to the physical contact involved in infractions of the rules, within reasonable limits. But by playing hockey do you consent to having a stick swung at your head?
Unfortunately, until five or 10 years ago, the answer was yes. There had been arrests made in Canada (mostly involving hockey players), but there had been very few convictions registered even if serious injury or death had occurred by stick-swimming or some other offensive means.
Fortunately, times have changed to some extent. Assuming it is not legitimate case of self-defense, the courts are getting tougher about violence that is clearly beyond the realm of what a player should expect in the normal course of a game. There have been cases of offenders being convicted and even sent to jail.
We must expect some rough play if we choose to play a contact sport. But, that does not mean we consent to being assaulted.