Which portlet id are we talking about? The id in the portlet.xml file, or the internal id of the portal server?
Remember, the same portlet can appear on a page twice. Data encoded by one instance should not be visible to the other instance.
From the
JavaDoc:
The encodeURL method may include the session ID and other portal/portlet-container specific information into the URL. If encoding is not needed, it returns the URL unchanged.
So, it looks like the encoding is left up the the vendor. But as long as it works, we shouldn't worry about how it works, should we? All faith must be blind faith.
-Cameron McKenzie