I understand where the message comes from, but it's an unusual message to get when registering what seems like a "first-party" account. If it's your domain and

I understand where the message comes from, but it's an unusual message to get when registering what seems like a "first-party" account. If it's your domain and your app, they're in the same trust domain, so you could reasonably just trust it automatically. (Google doesn't prompt when you log into YouTube using your Google account, for instance.)