That is part of the Rupert Murdoch controversy: many (all?) of the News Corp. properties are behind a paywall, but the paywall has a hole in it the size of Google. ;-) Google pays them (but not enough to stop them from complaining) and indexes their sites. They intentionally allow users coming from a Google search to enter their fiefdom, but throw up a paywall for direct links.
They have a serious conundrum: they want to be indexed by Google so that they can attract visitors, but they want to be paid by subscriptions (paywall), which is more lucrative than advertisements (assuming they can convert visitors into subscribers).
Even if they closed the "referred by Google" hole, they would still have to allow the googlebot unfettered access in order to index their site. This would make the hole slightly more obscure, but it would not close it.
