The schema in annex C is not as restrictive as the prose it describes (cf. sections 7.1.1, 7.1.4, or 7.1.5). The annex's prefix ensures that the prose takes precedence and so this isn't intrinsically a bug.
That said, one could create an additional schema file that restricts the XML Encryption as used by the ETM. This would allow for a more accurate representation of the prose within the constraints of an XML schema.
The schema in annex C is not as restrictive as the prose it describes (cf. sections 7.1.1, 7.1.4, or 7.1.5). The annex's prefix ensures that the prose takes precedence and so this isn't intrinsically a bug.
That said, one could create an additional schema file that restricts the XML Encryption as used by the ETM. This would allow for a more accurate representation of the prose within the constraints of an XML schema.
Alternatively: make the schema informative.