I didn't realise I missed a point to address, I'll seek to clarify.
It's always the user's choice as to whether to send referrers or not, as the referrer is actually added by the user's web browser itself. Extensions exist for just about every major web browser[1][2][...] to modify the behaviour of the HTTP Referrer field. If you don't like the idea of sending referrers, it's entirely within your control to never send a single referrer.
In almost all cases, disabling the referrer entirely won't result in any broken behaviour, primarily as the HTTP Referrer is unreliable and can be spoofed anyway.
I'm not saying that I totally agree with kijin, but I don't think your answer addresses his point.