Hi Richard,
I was incorrect about the Introscope SOAP Web Services API being accessible using "/data/query?" because it fails for me.
I have now realised that "/data/query?" is only useable when you have the add-on Easy Integration Kit installed which is available here:easyintegrationtoolkit.zip Also this related Queries.zip
"Easy Integration Toolkit is a web application that plugs into the Introscope Enterprise Manager and serves up data in response to HTTP queries."
So you need to undeploy that application (data.war) to disallow the queries.
(I will also rename the title of this question so the correct subject is more visible for the future)
Hope that helps
Regards,
Lynn