Correct: Default is to scan, setting disables that.

Plus, the XSD specification clearly says that defaults only apply to empty elements; not absent elements. The meaning of an absent element is contextually defined (in this case, by the persistence spec). The meaning of an absent element is not specifyable in the XSD.

http://www.codesynthesis.com/pipermail/xsd-users/2008-August/001885.html