Good work m8, that's seems logical! The network connections have two purposes not only to get keys if needed(should not be in regular interval) & to get data(how many are using the rcv & what particular channels they are always viewing). Some members who are expert on this things can patch the software itself so the receiver will function without network connections.
The firmware is like a built-in spyware taking data(as mentioned above) to be transmitted to the server. And its easy for them to identify you since you got a fix ip address when using adsl/dsl.