Um, yeah, movie studios may choose not to preview movies they fear will get unfavorable reviews. That's not the same thing as, say, sending DVDs of the movie only to reviewers they can count on for favorable reviews. When a studio refuses to offer a preview screening for a film, that's a red flag to reviewers and the non-reviewers alike, and is often commented upon by the reviewers. If a PR company gives a review copy to IGN, Gamespy, and Gamespot but not Eurogamer, The Escapist, and Edge (to site a purely random and hypothetical selection example), what happens is not that the audience gets a red flag- what happens is that the prior three get the competitive advantage of being able to "scoop" their competitors on coverage of the hot new title while the consumer who has reason to believe they're getting a review judging the game on its merits and the reviewers who are left out in the cold get screwed.
Redner shouldn't have been threatened; that's just wrong. But for Christ's sake, let's not pretend for one second that, "Well, this is standard procedure for the PR industry" is in any way equivalent to "this is morally acceptable" or even "this is good for the industry."
Companies are at pains these days to pressure consumers to purchase games while they're shiny and fresh, if not pre-order them before any criticism can surface. If this is the way things are going to be done- if we're going to be told with a straight face that this is the standard way things are going to be done- then as consumers, our duty becomes to accept only reviews from outlets that publish after the general consumer release date, because those become the only outlets worthy of trust. And to presume that anyone who publishes a review a week or more before the general release is nothing but a company shill with better letterhead.