I think this sounds better: 

element_form_default

Savon should extract whether to qualify elements from the WSDL. If there is no WSDL, Savon defaults to :unqualified.

If you specified a WSDL but still need to use this option, please open an issue and make sure to add your WSDL for debugging. Savon currently does not support WSDL imports, so in case your service imports its type definitions from another file, the element_form_default value might be wrong.