We had this up as a rumour yesterday, and I'd say IGN UK's review of Metal Gear Solid 4: Guns of the Patriots pretty much confirms it. "In return for letting us play Metal Gear Solid 4 before its release, Konami issued us with a list of things that we're not allowed to discuss. This list of prohibited topics is pretty long, and even extends as far as several facts that the company itself has already made public." Might that be the length of the cutscenes (upwards of 90 -gasp- minutes)?
IGN doesn't say in a strongly positive review, but for that icky first paragraph. They wanted to do the write-up as spoiler-free as possible, which makes a lot of the verboten stuff something IGN wasn't going to mention anyway. Still, they acknowledge Konami's heavy-handedness, apparently beyond the pale of normal pre-release review requests.
By the by, IGN calls it "the ultimate Metal game. Without question," but it's only ranked by IGN UK so far, at 9.9. I think it's safe to say the US ranking will conform. This is one of those games that's pretty much review proof. Konami's micromanagement might piss off only the writers, but that doesn't mean it isn't also unnecessary.