Only to an extent. Once someone has access to the source, anyone could pirate or reverse engineer it, which seems to be the GP's concern.
However, this isn't necessarily any different than binary executables, which we know experience a fair amount of pirating.
Also from that FAQ:
"Update your app frequently, so that only authorized users will always have the latest, greatest version of the app. Distributing updates is easy, thanks to Chrome's support for autoupdate. You just increment the version number in the manifest, update the ZIP file, and then use the Chrome Developer Dashboard to upload and publish the updated ZIP file. Over the next few hours, the new version of the app starts going out to its existing users."
"Don't put any roadblocks in front of users. Your app should be easy to buy, and it should work everywhere users want it to work."
That is: "Don't rely on DRM to protect you. It won't work, and you'll piss your users off."
