XForms CR - 3.2.1 Illegal Requirement?

In 3.2.1 it is stated, "A host language must include an attribute of type 
xsd:ID on each XForms element.".

I assume that the term "include" means "add".

An <xforms:model> element may already possess an id attribute and must do so 
if there is more than one <xforms:model> element. If the host language adds a 
further attribute of type xsd:ID it seems to me that this may violate a 
validity constraint expressed in 3.3.1 of the XML 1.0 Recommendation (2nd 
Edition). It may also violate Chapter 3.4.4 of Part 1 of the W3C XML Schema 
Recommendation.

Comments?

I would also like to ask *why* a host language "must" add an attribute of 
type xsd:ID to every XForms element.

Andrew Watt