Element and attribute names can be qualified or unqualified if they are declared "locally".

Most attributes are declared in the context of declaring the element.

You could force them to be "qualified" and require a namespace name/prefix, but that isn't what people normally do.

On the other hand, for elements declared locally (next slide), there is no such "normal" way.

You can setup schema defaults by setting the 'attributeFormDefault' and 'elementFormDefault' attributes on the 'schema' element:

<xs:schema elementFormDefault="qualified">

</xs:schema>