From what I can see (my in-laws use them) if you are signed in to apps that rely on their SSO then you are good. If you need to login or if your token need to refresh then you’re screwed. If you are just watching broadcast you’re also good.

But we were trying to watch HGTV on Apple TV, got kicked out of an already logged in session, and now have no way to log back in. I can’t imagine they will have any choice but to issue at least some refunds if this goes much longer.