Disabling ALL roaming? It's relatively easy to disable data roaming on an Android device in the "Wireless &amp; networks" settings section, but the phone still tries to connect to other services via roaming like voice and SMS.  Is there a way to disable ALL roaming whatsoever?  I know about airplane mode, but that completely disables all connectivity, and it's also annoying to have to remember to keep turning airplane mode off and on again when I enter/leave the vicinity of this network.  I'd like to be able to connect to my network but not allow any roaming.

Why disable?  Becuase the network offering the roaming isn't one I trust, as I think it may be intercepting and recording my data.  So I don't want my phone to use it.
I don't think this is possible. 

I think when carriers agree to let users roam on each others use their network, that probably their policies would comply in the way that when you can trust your carrier, you can probably trust it when it trusts the other one.

EDIT: Actually I recently found this out:
When you go to Settings > Wireless and Networks > Mobile networks > Network operators, you can choose to select your network manually instead of having it done automatically. But in fact, I'm not sure what it will do when you go out of coverage of the network you chose.