kaled - 4:02 pm on Oct 9, 2010 (gmt 0)
How can something your browser broadcasts be in invasion?
Let us suppose that the first search engines (including Google) used POST rather than GET for some arbitrary reason. Let us further suppose that Google decided to switch to GET. Without a doubt, everyone here would be up in arms claiming this was just another sign of Google's contempt for privacy - and maybe you would agree with them.
Since it's easy, it is entirely reasonable that search engines offer the option to hide referrer data. If it was difficult, then the arguments would be different, but that's not the case - it's trivially simple.