I think this is very different from Ewanchuk, because it relies on an absence of evidence of actual consent. The way the wording is provided is where “there is no evidence” of actual consent, either “by words” or by actions on the part of the person who would be giving the consent.
To rely on the absence of evidence as supportive of the fact that consent wasn't obtained, and as preventative of arguing the issue of mistaken belief in consent, puts an impossible hurdle in front of the defence in these types of situations, because it's watering it down to an issue of just the facts, and if the facts aren't even disclosed by the complainant.... While the crown has a proactive obligation to disclose all of the evidence in their possession, the complainant doesn't.
We saw this in Ghomeshi. We see this in cases all the time where there's information the complainants don't reveal to the crown that comes up in the course of trial.
If you say you can rely on “no evidence” to substantiate essentially a conviction, then you're allowing complainants to get away with not disclosing things that might undermine the validity of their complaint, and hamstringing the crown into a position of not being able to disclose a case because there's no obligation on the complainant to disclose it to the crown, to then disclose it to the defence. I think the way it's worded—and perhaps it's an issue of tweaking the wording—makes it an issue about the factual circumstances, not the legal circumstances.