Canada

I agree but we don't even have to get that far. No institution should rely on SIN secrecy. It's as simple as that. It should be treated as semi-publicly available information like birthdates and important stuff like opening a bank account should require more factors of authentication.

Several countries don't create these secret numbers that "no one should have but you" without having to rely on revoke-able tokens and whatnot. Like many things, crypto has a clever solution for this but the current status quo is so bad that a not-stupid approach would already be quite the improvement.