I haven't had a chance to verify this myself, but according to Marco, this does not actually avoid the iCloud sync:
https://twitter.com/#!/marcoarment/status/124587437799374848
https://twitter.com/#!/marcoarment/status/124587437799374848
In fact, if you use UIManagedDocument, it creates a .nosync directory in the document bundle to prevent it from syncing in the framework itself.