With one note for you to consider: You don't seem to be acknowledging a person, male or female, who desires to be hurt in a sexual relationship. I'm sure you must be aware of same. If not then I can eleaborate.Because, your example is flawed and I can elaborate on that too later if you like. In the meantime you may want to try to imagine what 'would' be within bounds for S and M behaviour?
Practices and boundries are very clear within the BDSM community by necessity.
https://en.wikipedia.org/wiki/BDSM
It's not a community I understand or can relate to but I respect their right to choose as long as they aren't paying people to submit and I place no judgement on them regardless of the role they choose to play within the community.
I had a look at your link and then went to "Canada", expecting to find limits defined on S and M Behaviour. I found next to nothing so now I'm going to ask you to direct me to your reference. Or if you choose, tell me what you have found to say that some acts are not within the law. I'm specifically referring to a closed fist punch to the side of the head. Legal or illegal?
I don't think there are any laws specific to BDSM. Assault is illegal period. No exceptions, not even with a contract. Because of that practitioners of BDSM have had to be extremely careful to make absolutely sure everything is consentual and doesn't require medical attention.
All I got out of that is that they have to be sure everything is consensual. I hope not.
Well, maybe we're getting closer because we know that murder, suicide and manslaughter aren't legal.