First of all, Bill C-15 is not law yet; it has to be passed by Parliament.
Second, the obligation to not act in contravention of the conflict of interest is there. You posit that he will make an exemption that benefits himself and people will not know about it.
I always have difficulty answering a hypothetical question. If you give me an actual case or an actual fact, I can answer it. I don't quite see how we can have a secret exemption. The effect of the exemption will be public and people will ask, like you, why this company is doing it, when normally an act would require A, B, and C. Where do they get the authority?
Therefore, somebody will say that there is an exemption and here it is.