C2DM Unregister Issues
It turns out when you follow the client-side C2DM unregistration process, this does not guarantee that those registration tokens are permanently unregistered for that device.
If we unregister as specified above and then send a push notification to that registration_id, the server receives an Error=NotRegistered as expected.
But, unexpectedly, when that device re-register with C2DM (and getting a new registration_id), the old registration_id is reactivated as well and can receive push notifications and does not result in a server-side Error=NotRegistered.
The end result: we implemented our server-side API to take both the new and old registration_ids when the Android client successfully registers with C2DM, allowing us to manually delete the old registration_id.
Drawable XML Files
Prefixing the name of a drawable xml file with “active_” seems to prevent android from using that drawable at all.