namespace-less atts in its:spans in test suite

Hello again,
I have a question about the usage of <its:span> in some of the ITS test
suite XML files. For example, locqualityissue10xml.xml has "<its:span
locQualityIssueComment="Senten...". I'm wondering if it is correct that
locQualityIussueComment isn't prefixed with "its:". When processing this
file, LibXML tells me that locQualityIssueComment is in the null
namespace. Section
6.2 <http://www.w3.org/TR/REC-xml-names/#defaulting> of the XML namespace
specification seems to agree: "the namespace name for an unprefixed
attribute name always has no value". Is this something that needs to be
fixed in the test suite, or is there an error in my understanding? I count
about 16 files that use unprefixed ITS attributes in an <its:span>.

Nathan