Originally Posted by SolApathy
It is using the account attached to the SIM. The phone will not work with the Sprint SIM due to the bad ESN. You are seeing the roaming symbol because you are using a 3rd party SIM in a Sprint phone. You will not get any signal when not in Roaming mode because when you are in "no roaming mode" it is only looking for Sprint towers which don't exist where you are.
So you say that the phone will continue to work with RUIM irrespective of the fact that the services of the Sprint account it is attached(assuming it is) are suspended. I did receive a message the first time I put sim & connected that the service will soon be suspended or something like that, which looked like from sprint, I can't remember exactly though.