Word is Apple has a better technical fight than it does a legal.
The EULA doesn't have enough power to close them shut.
But since Psystar uses the standard OSX, Apple has the power to disable it with updates.
You can get away with not updating your iPhone, but not your OS.
You end up missing out on features & stability.
Plus, its hard to establish a business and tell your customers you can't update.
And Apple can even throw in the lock with Quicktime and iTunes.