Well as far as I know you do not need to use CDATA sections to generate standards complaint XML.
CDATA is just a way to insert data in a document without having to encode it, as explained here:
en.wikipedia.org/wiki/CDATA
For instance:
<tag><![CDATA[
<html>
]]></tag>
is the same as:
<tag><html></tag>
The advantage of using CDATA sections is that you do not have to encode special characters like <, > and " .
Anyway, since the XML writer class encodes the data for you automatically when the document is generated, you do not need to use CDATA sections.