“At my company, our lawyers advised us to keep what we considered more-or-less public software under NDA for a very long time because demoing software to someone under NDA, no matter how many people it is, avoids ‘publishing’ the software and any inventions contained therein.”
While John finds this credible, I’m going to call “bullshit” on this. Software is published the moment it is made available for sale. The iPhone is for sale. Keeping a tiny subset of customers under NDA will not affect that.
Of course, some might argue that there’s something specific about the APIs which is patentable, but this is unlikely. Remember that patents don’t cover the specifics of code.
My guess is there some unspecified legal snafu, but I don’t think this is it.