Problem: upon returning from a 2nd activity the first activity's listview does not reflect database changes made by the 2nd activity. If I make a trivial change to code (to make emulator happy) and refire the app the listview now accurately shows the database changes the 2nd Activity made during the last session.
The guts of the app:
MainActivity: extends Activity implements LoaderManager.LoaderCallbacks<Cursor>
=>onCreate: SimpleCursorAdapter set; getLoaderManager().initLoader(LOADER_ID, null, this)
=>onResume: super.onResume(); getLoaderManager().restartLoader(0, null, this)
...oh my gawd! There's the problem: initLoader and restartLoader are using different loader ID's.
This stumped me for the last five hours. Why I am leaving this question: in trying to solve my problem I didn't run into this answer (maybe it's just too bone-headed of a thing to suggest someone look for) but for the next person who stumbles in this unique way, here's a potential answer.