setPortletProperties on Producer Offered Portlet

The 1.0 primer has the following statement:


      6.1.2 Portlet Lifecycle

   e. setPortletProperties: Consumers can invoke this operation to
      modify the values of properties of a consumer-configured portlet.

However, this is not codified in either spec or as a conformance 
statement. What should happen if a setPortletProperties() call is made 
against a POP?

Thanks,

Nate