How's this for a consipiracy theory. Canon intentionally leaks the photos and "release" date knowing they will stir the blogosphere into a wild feeding frenzy. Then when the sharks are circling in for the kill, they clamp down really hard to seal off any more info getting out and let the "release" date pass with no announcement. One week goes by, two week, maybe a month. By then, all credibility in CR as a reliable source of Canon product information has been uterly destroyed. Canon can now continue to operate securely in to the future knowing that anything that comes out on CR, regardlss of confidence level, will be completely dismissed out of hand. (I don't really believe any of that. Just thought I would throw a little blood in the water )
The first part of your theory makes complete sense.
About the second part, I am positive that from Canon's perspective a site like this does a lot more good than harm. Let's face it, the harm is almost non-existent. It's not like Craig is posting roadmaps or detailed product specs years in advance or other information that competitors don't have. Most of the solid information comes very near to the announcement date and even then it's very limited in details.
On the other hand, a site like this generates ongoing "news" and brand coverage even when Canon don't have anything to announce or tell us. This kind of free and continuous publicity is priceless. Furthermore, I am positive that the buzz generated before an announcement, even if it "spoils" most of the surprises, is directly translatable to more preorder sales than if we just have waken up one day to a new model on the market.
So, in the end, while Canon might be a bit annoyed from time to time from this site, I am sure they know that they are better off with it on the air than not.
This place is free marketing for them