As you said, you can't turn over an SCC decision, which is why outlawing prostitution won't happen, unless the Nonwithstanding Clause is invoked. But as Moviefan pointed out in the next post after this one, Harper's lack of grandstanding on the issue speaks volumes.
Exploitation is covered under different codes, depending on the circumstance: Illegal labour, child labour, forcible confinement, assault, threat of bodily harm, etc...
I'm a political science grad, not a lawyer, so I don't recall which specific laws they are, but they were referred to in the initial Ontario challenge, and subsequent appeal.
