Ah yes, you're right. I spoke to soon. I just checked on the latest Beta simulator and, sure enough, it is checked, with a fresh install and no iCloud account.

Ah yes, you're right. I spoke to soon. I just checked on the latest Beta simulator and, sure enough, it is checked, with a fresh install and no iCloud account. At least that proves the service is accessible anonymously (i.e., without an identifying iCloud token)