I'm not sure why some people are having problems, but I am testing this extension as we speak, and it's working fine.
When I go to Google, or Google Maps without the extension, Google is tracking my location and redirects both the search page to the local one (something I HATE so much that is the reason why I don't use google!), and pinpoints my location in Maps.
With the extension enabled, Google sees me as if I am in the US, and can't find me in Maps.
And the extension is NOT blocking gmail.
So. the extension IS working, and it's really protecting my privacy.