Welcome to the club.
I do have to clarify that Shaker Robotics hasn't shared everything before, though it's less intentional omission and more "we're not actually that exciting". We also want to make sure teams experience the engineering design process and don't get hung up with preconceived notions of what is possible. That being said, we're going more or less open as well.
There's simply so much to gain and so little to lose. We personally will gain awareness, attention, and design critiques, and if we happen to do things well then the community at large will learn about a potentially viable design. What is 2791 going to lose? A competitive edge? If we honestly get beaten by our own mechanism, we'll have exceeded our goals for the year. How cool would it be to see your prototype more or less on Einstein?
I'm glad you guys on 1529 are following suit. You guys definitely have crazy, innovative ideas and I'd love to check on what you guys are doing as the season progresses.
As to where that will be "open", be it CD or my blog, I'm not sure yet... Probably major prototypes and designs on CD, more details on my blog.