Sample Illegal Schemas
<![CDATA[<xs:sequence>
<xs:element name="first" type="xs:string" />
<xs:element name="last" type="xs:string" minOccurs="0"/>
<xs:any namespace="##any"/>
</xs:sequence>
]]>
<![CDATA[<xs:sequence>
<xs:element name="first" type="xs:string" />
<xs:element ref="otherns:foo" minOccurs="0"/>
<xs:any namespace="##other"/>
</xs:sequence>
]]>
- Choice of optional element OR wildcard
- Can't write schema to control where otherns:foo occurs
