It's also a question of democracy, because even if they say they'll get consent, and 10% of the public decides to opt in, they are still obtaining information—good stuff, and good news stories, potentially—that can sway them democratically.
There is a whole different question that I think we haven't talked about in terms of the need to protect the democratic equality of citizens, both those who choose to opt in and those who choose not to. If they are dealing with government, it's because they have to deal with government and because they have to fix a problem with their SIN card or CRA. That's why they obtain it, not so they're receiving that information.
To me, it's like the consent boxes that we have for private business right now. If government used them, they'd be laughing all the way to the election.