It makes little sense to stifle pre-release hype from free review sources (or for the cost of a review kit) unless they had reason to believe that the reviews would be counterproductive to their extensive Kinect marketing campaign.
The thing is, it's largely unnecessary to try and control initial public opinion of Kinect because as it's already been pointed out, the majority of potential Kinect consumers don't read or follow video game specific press.
Now a bad review on Yahoo or MSN (ha ha) that reaches the mainstream consumer could potentially turn off would be buyers, but mainstream press reviews will do the job, positive or negative, even if published on release day or after.
And by the same token, a flood of bad reviews from the video game press after release will still have the same postive/negative effect on its target audience, with the key difference being that the gamer audience is the type that would pre-order, camp out/midnight launch pick up and or cancel a pre-order on the basis of particularly bad reviews from trusted sources.
Kinect is one of those products that really has to be tried hands on to get a legitimate opinion of anyway, so it will ultimately be word of mouth from early adopters that have the biggest impact on overall adoption rates.