question on insecure Id/ID/id search method

[scorpion]

This question is more XML Security (and specifically, on the
Apache XML security implementation).

When I sign or open signed XML document, I see the
following warning:

....
WARNING: Found an Element using an insecure Id/ID/id search method:
claim:StreetAndNumber
Apr 27, 2004 3:41:10 PM org.apache.xml.security.utils.IdResolver
getElementById
WARNING: Found an Element using an insecure Id/ID/id search method:
claim:City
Apr 27, 2004 3:41:10 PM org.apache.xml.security.utils.IdResolver
getElementById
WARNING: Found an Element using an insecure Id/ID/id search method:
claim:State
Apr 27, 2004 3:41:11 PM org.apache.xml.security.utils.IdResolver
getElementById
WARNING: Found an Element using an insecure Id/ID/id search method:
claim:Zip
Apr 27, 2004 3:41:11 PM org.apache.xml.security.utils.IdResolver
getElementById
....

What does that mean exactly?

TIA.