> I don't know, does apple ignore it?

No, it doesn't. I know because I had issues once enabling it and Apple customer support asked me to talk to my carrier if tethering was enabled for me. I was irritated when I heard this as I thought they are just "passing the buck" to someone else, and unnecessarily became rude and told them that indian carriers don't have such nonsense and stop bringing US practices to India. (Turns out they were partially right - you had to add a carrier specific username in the APN settings, as Apple didn't have it in its carrier database).