Earlier quoted context omitted.
What's the difference with emergency calls? (I know nothing of this.)
I don't know how it is with VoLTE and other recent things (it may be the same; it may be different), but at one time in cellular world: Emergency calls differed from other calls in that they Must Always Work. An emergency call can connect using any tower that is compatible with the caller's hardware -- with or without service provisioned, and with or without any sort of SIM. Need help, and find a dusty phone somewher…
In my country, at least on my Samsung Galaxy mobile device, they are sending Flash Messages for ads, even though I requested to be removed from their lists (and they complied... with calls and SMS).
I already see them making use of this for ads until a big group of people complain.
I'm tired, boss.