My read is that they're simply restricting access to pre-release versions. Once released, it's Open Source, and same as usual.
How long does pre-release last? The Motorola
Xoom has Honeycomb on it, and has been in consumers hands for over a month. Either Google is admitting they ship pre-release quality products and charge people money for that, or Motorola shipped before Honeycomb was done.
Heck, call RedHat a "closed" company if that's how you think, because they do the same thing.
Source for RHEL 6 was available when it went into beta, in April 2010. RHEL 6 was in pre-release mode until November 2010. Thats a window of 7 months where source was available before they shipped a final product. Big difference between that timing and the situation with Honeycomb. That 7 month window allowed CentOS, and Scientific Linux to also continue their work as normal. The community would have been up in arms had RedHat held back the code while shipping public beta versions.