I didn't realize that GoogleVoice's VoiceMail had so many annoying quirks in it!

I tested the fallback mode (using one revision back), and found a problem caused by one of these quirks.

If you have any new voicemail messages waiting, GV VoiceMail will start playing them immediately .
And sending the "2" (for DISA calling), will instead cause you to reply to the VoiceMail that is currently being played!

To make matters worse, you need to add some pausing at this point.

So, assuming a message is waiting, you need to send "{pause} * {pause} 2".

If there is no message waiting; this sequence should still work (although it will cause the "I'm sorry; I didn't catch that..." message).