I would just note that the section you're referring to is in the Bank of Canada Act as it stands. It's for drafting purposes, and that's been repeated. The current subparagraph 18(g.1) says:
if the Governor is of the opinion that there is a severe and unusual stress on a financial market or financial system, buy and sell any other securities...to the extent determined necessary by the Governor for the purpose of promoting the stability of the Canadian financial system.
So that's a power that's already there. The change is really the proposed subparagraph above that, in proposed section 146, which gives the governor the authority, even when he is not of the opinion that there is a severe and unusual financial stress, to establish a list of securities in which the Bank of Canada will conduct open market operations.