Yes. https://en.wikipedia.org/wiki/Signaling_(telecommunications)

> Apple and the carrier are also "other people."

Don’t be silly.

> Whose phone is it anyway?

Whoever bought the phone.

> Any action taken by a device one controls should be made transparent and auditable by the device's owner.

Ok, this is a moral and ideological position in favor of all designs of all silicon, all circuitry, and and all software being entirely open source.

It’s valid to argue that we should live in such a world, but it’s not an argument that Apple using SMS for signaling is equivalent to malware. Sorry.

> They are meant to be tools,

They are tools.

> not undomesticated semi-wild animals with a will and mind of their own.

Weird analogy to use to describe signaling traffic.