XMI12 — XMI 1.2: Missing class scope in <7m:AttName>, pp. 6-6?

Given a model "Acme" consisting of a class "Wiz", with a string-valued
attribute "name", two types of model instance encoding are possible. Either
this, using the <8a:ContentElement> production:

<Acme:Wiz>
<Acme:Wiz.name>foo</Acme:Wiz.name>
</Acme:Wiz>

or this, using the <7i:DataValueAtt> production:

<Acme:Wiz name="foo"/>

At best, the lack of a namespace and class scope identifier in the last
example is inconsistent. But I suspect that the inclusion of a class scope
in the former is intended to support instances implementing classes with an
overlap in attribute names - e.g.:

// The Acme model:
class Base

class Derived: Base

(I'm not familiar enough with the MOF to know if this is allowed, but it
appears to be the only possible rationale for scoping attribute names in the
<8a:ContentElement> production)

Using the <8a:ContentElement> production, a "Derived" instance is easily
represented:

<Acme:Derived>
<Acme:Derived.name>foo</Acme:Derived.name>
<Acme:Base.name>bar</Acme:Base.name>
</Acme:Derived>

However, using the <7i:DataValueAtt> production, things get ambiguous:

<Acme:Derived name="foo"/>

Which "name" value is being specified here? Base.name or Derived.name?

If the XML atrribute names were scoped, this would not be a problem:

<Acme:Derived Acme:Derived.name="foo" Acme:Base.name="bar"/>