Some links for testing referrer stripping manually.
http://www.google.com/search?q=;
http://www.google.com/search?q=x&lang=en
http://www.google.com/search?q=x;lang=en
http://www.google.com/search?q="
http://www.google.com/search?q='
http://www.google.com/search?q=<
http://www.google.com/search?q=>