Something frequently (willfully) misunderstood in politics is that you do not need to bribe people to say things in your favor. It is much easier to find someone who is already on your side and promote/support them. That think tank is not saying nice things about Wal-Mart because Wal-Mart is funding them; Wal-Mart is funding them because they are the kind of shop that will say nice thinkgs about Wal-Mart. Bribing a senator is more expensive and uncertain than funding the campaign of the guy who already agrees with you.
Syncaine has not been bribed to say nice things about Darkfall. Darkfall is funding its most passionate advocate in the hopes that he just keeps talking. These companies give away accounts and free time as promotions anyway, so why not pass some to someone who will promote your game in the process?
For we the gaming bloggers, the key is removing barriers to play. If the game is there and available, odds are better that I will play, odds are better than I will write about it. I phrase many things in terms of LotRO because I have the lifetime account, so it is always there, ready, never needing that decision point about re-subscribing. $15/month is nothing to me, but the trivial inconvenience of re-subscribing and allocating my attention across multiple games is a barrier. If Blizzard granted me free play, heck, half a dozen friends re-subscribed last month, I would join them occasionally. And then I would find myself noticing and commenting on patch notes, events, etc. Were we not such a bunch of hate-filled vipers who constantly attack the games we play, I would be surprised that so few developers have offered bloggers free play.
Bloggers are not like the advertising-funded sites and magazines. Even if we have ads, they are usually through an ad network rather than a direct relationship with a publisher. It is hard to buy good blog reviews, although you could try buying goodwill with a bit of swag. You can buy attention, which may or may not be an issue for you the reader, and which may be an issue for the publisher given how much venom we have in the blogosphere. And, of course, full disclosure.
I have not bothered to keep track of whether I got into betas randomly or as “press,” not that I visit many betas these days. I don’t have anything to disclose for live games. I receive few bribe offers. I want a pony.