I don't see how this is not open source yet. Just because they are limiting access to the actual source doesn't mean that, when you finally do get past the invite wall and see the source, you don't have all the open rights they assign to it.
It's open source behind an invite wall. Once you get it, it should come with the OSS lincenses. I'm assuming.
It's open source insofar as the code, when it is released, will be released under an open licence. However, it fails the 'unofficial' criterion of a project that is developed in the open. See also: http://www.youtube.com/watch?v=0SARbwvhupQ
It's open source behind an invite wall. Once you get it, it should come with the OSS lincenses. I'm assuming.