How come unparsing invalid XML doesn't produce an error?

[Costello, Roger L.]

Hello DFDL community,

This is a follow-up to the thread that Christofer started last week about 
"fixed" values.

My input file consists of integers, on different lines. The first value in the 
file must be 44.

Using --Validate limited, I get an error message when the first value is not 44.

If the XML document is invalid (the first element does not have a value of 44), 
then I want unparsing to generate an error. I thought that Steve said the way 
to achieve this is to use:

dfdl:outputValueCalc="{ 44 }"

However, that does not result in an error. Why not?

Here is my DFDL schema:

<xs:element name="input">
    <xs:complexType>
        <xs:sequence dfdl:separator="%NL;" dfdl:separatorPosition="infix">
            <xs:element name="Fixed-Value" dfdl:occursCountKind="implicit"
                                  dfdl:outputValueCalc="{ 44 }">
                <xs:simpleType>
                    <xs:restriction base="xs:byte">
                        <xs:minInclusive value="44" />
                        <xs:maxInclusive value="44" />
                    </xs:restriction>
                </xs:simpleType>
            </xs:element>
            <xs:element name="num" type="xs:string" maxOccurs="unbounded"
                                  dfdl:occursCountKind="implicit" />
        </xs:sequence>
    </xs:complexType>
</xs:element>