Yeah, its seems in Canada law it depends on the circumstances. You can't consent if you're unconscious or if you've been drugged, or coerced... and, yeah, those seem to me like obvious cases of rape. But going by this article, two people being drunk doesn't automatically negate consent so long as they're both aware and willing.

Article Summary:

Consent is defined in the Criminal Code as "voluntary agreement of the complainant to engage in the sexual activity in question." Janine Benedet, a law professor at the University of British Columbia's Peter A. Allard School of Law, puts it this way: "The question is whether the person in their own mind wanted this sexual activity to take place." According to the code, no consent is obtained when the agreement comes from someone other than the complainant, the person is incapable of consenting or is induced by the accused abusing a position of trust, power or authority. Consent also does not exist if someone "expresses, by words or conduct, a lack of agreement to engage in the activity" or if the complainant, who previously consented, expresses "a lack of agreement to continue to engage in the activity."

In that decision, the court wrote that "when the complainant loses consciousness, she loses the ability to either oppose or consent to the sexual activity that occurs. "Finding that such a person is consenting would effectively negate the right of the complainant to change her mind at any point in the sexual encounter."

The code says there is no consent where someone is incapable of consenting. Various factors affect an individual's capacity to voluntarily agree to sexual activity, according to Canadian law. One factor courts sometimes consider is whether the accused was in a position of authority, said Benedet. "There are provisions in the Criminal Code that talk about consent being vitiated when someone is in a position of trust or authority," she said. Despite the idea of a position of trust impairing the ability for there to be consent, Benedet said there continues to be debate in the case law about "what kind of relationship really puts you in a position of authority."

Intoxication is also considered a factor that affects a complainant's capacity to consent to sexual activity. But in practice, Benedet said, the threshold of intoxication at which point someone is deemed incapable of consent varies depending on the circumstances. Where a complainant becomes intoxicated involuntarily, for instance, by being drugged, "courts [tend] to be very generous in terms of what level of intoxication would be sufficient to amount to incapacity." If a complainant consumes drugs or alcohol by choice, courts have "a very high threshold for incapacity, much higher than they would have applied in those involuntary intoxication cases."