I think you misunderstand — this seems to have been claudius' point:
> Note that usually it's best to allow requests that have no referrer header at all, otherwise you'll be blocking some legitimate viewers of your site.
It was probably a badly-placed reply; my point was to illustrate a use for referrer headers and to state that sites blocking based on the lack of a referrer were doing it wrong.
> Note that usually it's best to allow requests that have no referrer header at all, otherwise you'll be blocking some legitimate viewers of your site.