It would probably just result in games not being for sale in Canada.
Maybe a progressive tax, not a ban, eg if your game grosses say $1M sales in Canada you pay a higher tax rate if you don't attest that you've set aside enough cash to do this when you sunset the game. Then if you said you'd do it but don't, the CRA can come after you. Revenue from this tax could be earmarked for computer education or indie studio grants or something.