I would like to address the reverse onus, specifically regarding proving that a relationship is not exploitive.
By saying that you can prove that a relationship is non-exploitive in a court of law, what you are saying is that this isn't a black and white issue. There are grey areas. There are areas where people may have non-exploitive relationships.
Also, if that provision were enacted, this would take the burden of proof--that is, the assumption of innocence until proven guilty--and turn it on its head. That's unconstitutional under the Canadian Charter of Rights and Freedoms, and I can't see that as being a realistic provision.