I think comment #8 nailed it. The nonsense from the Chromium people trying to rationalize this is beyond ridiculous. If a user installs an extension manually, it is not force-installed, and surely the browser can remember this one important bit of information as part of the extension profile. I don't see any other reason than just to force everything through the Chrome store, and that annoys me. Edit: By the way, I don't think Opera has that kind of annoying bubble (not sure though). Maybe worth trying?