Starting in Xerces-J 1.4 (possibly earlier but I just noticed it) the
sax.SAXCOunt validator ignores all attributes used to declare namespaces. e.g.
it thinks that this document is valid:

<!DOCTYPE test [
  <!ELEMENT test (#PCDATA)>
]>
<test xmlns="http://www.example.com/">
  Hello
</test>


It also seems to be ignoring schema location attributes so that this doucment is
DTD valid:

<!DOCTYPE test [
  <!ELEMENT test (#PCDATA)>
]>
<test 
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.example.com/">
  Hello
</test>

dom.DOMCount has the same problem