[ricardobeat]

Operators in Brazil have done this forever. The phone's ID is probably already sent along when you activate the SIM card, why would a company not do this?

[tresta]

They do it here in Sweden as well (or at least they did ten years ago). There's really no reason not to do this.

[cleverjake]

NOt that it is a /good/ reason, but the cost involved I implementing the system is often the reason listed as