I don't see why they'd fake it. I can see buying something and writing a review about it with the disclosure that it wasn't a paid post and the company wasn't involved, just to get the word out there about a great product. I think that's what many of us do here on HP when we write our review hubs.
I would think faking it would actually hurt the blog if the company ever found out, especially if it wasn't representing the company well.
As a Nuby Mommy Blogger, I have received items from Nuby for free to review and write about. I disclose that I have received the item with the intent to review and that the views are honest and mine. Having an actual company behind you helps to get your blog views, which in turn helps you to make money. I guess in return Nuby is getting advertising, so it works out for both of us.