Inspired by a brief experiment by Steve Garfield, I did my own 'outside broadcast' test, embedded below, using a bog standard Nokia hands-free hit. Darren - give this a try? [updated: video below should now work, I'd forgotten to set the 'Public' flag!]
If anything, I got too close to the headset remote control and my voice was a little distorted. But it proves the technique, hopefully. Give it a try in your own videos whenever there's external noise around, e.g. at trade shows!
Steve Litchfield, AllAboutSymbian and the Smartphones Show