Dunno 'bout Canada, but here in the US your legal standing is either innocent or guilty. Either you've paid your debt to society and you're off the hook, or you haven't and you're not...and that's the way it should be.
The big exception is that we've started doing Big-Brother-type surveillance on released sex offenders. I think that's wrong. If we're not going to let them actually be free, we should just keep 'em in jail. Better yet, give 'em a death sentence. Because if they're not "reformed" enough to turn 'em loose completely, they're not reformed enough to let out of jail period.
Once we invent this quasi-legal status of your-debt-is-paid-but-we're-keeping-tabs-on-you, you can apply it to anyone. Who's going to own the list of categories of people who get watched? What keeps us from putting most anyone under surveillance?
Who would be harmed? Us. By the precedent it sets.
I, BTW, am of the school of thought where sex predators get a life sentence. No parole, no chance to re-offend. Since we apparently do not have the stomach for that, I see nothing wrong with keeping tabs on them. For their protection as well as for the rest of society. If they don't like it, they could always ask to be kept incarcerated.