Yes, It's outside of Apples direct control but they don't actively discourage it either. They could insist upon nondisclosure agreements as some companies do (and yes sometimes those are a joke,) but really why would they.
Apple does insist upon NDAs. I've attended multiple Apple Developer conferences, and attendance is subject to agreeing to their NDA terms. And we're talking mostly about software here.
You can bet that any vendor working on any component for the latest Apple hardware is under a strict NDA. They're highly secretive about new products. The reason that the iPad won't be available for purchase for another 50+ days is that Apple held off submitting it to the FCC for approval until the last minute -- FCC submissions are public record.
