Yes, I did this last night, and the audio dropouts were gone. However, doesn't this mean that all the surround information that's directed to the center surround speaker will be lost?

I watched a good bit of Helm's Deep this way (CS on, 6.1 engaged, but no physical speaker), and indeed my rear soundfield did seem a bit lacking, but I'm no audiophile.

Perhaps there's a way to compensate for this? Possibly cranking the volume of the L & R surrounds?