Very strange situation that I cannot figure out.
So my goal is to have a completely locked down corporate device with No Apple ID. However, we would still like the ability to use FaceTime and iMessage. After some research, I discovered that supposedly you can't use iMessage and FaceTime unless you have an Apple ID. Fine.
My test group of 5-6 devices currently do not have Apple IDs signed in to them. I prevent this by disabling "Allow modifying device settings (Supervised Only)" so that they cannot sign into any accounts. Fine.
However, those devices, without Apple IDs, currently still have the ability to use iMessage and FaceTime. The strange part is, as soon as I uncheck "Allow modifying device settings (Supervised Only)" and give the phones the ability to sign in with an Apple ID (even though they don't sign in) the iMessage and FaceTime capabilities are removed and I can't use them. So I have no idea whats going on.
In summary, the devices have no Apple ID and have the ability to FaceTime/iMessage as long as "Allow modifying device settings (Supervised Only)" is off, which is what I want. But how is this happening? And can I replicate to 1200 devices when the time comes?