If a Default Keyword Value is configured for a Keyword Type on a document, and no other Keyword Value is assigned to that Keyword Type in the course of Advanced Capture processing (that is, a value is applied through Data Field Zone processing, an Advanced Capture form default, or manual pre-scan indexing), then the Default Keyword Value is automatically applied to the document. If Advanced Capture processing does assign a value to that Keyword Type, then the Default Keyword Value is not applied.
For more information on configuring Default Keyword Values, see the System Administration module reference guide.