Title: [policy-model]: group membership flatterning Colleagues - This appears to me to fall into the topic of "meta-policy". If this is true, then we agreed in Redwood City to specify a single meta-policy, while allowing others to define other meta-policies, if they so wished. The conclusion would be, that XACML would specify a single way of resolving the question that Simon raises, while acknowledging that this is just one of a number of possible choices. Personally, I favour relying on information that appears in the request, provided it meets the assurance requirements of the PDP (e.g. signed by a competent authority), because this is more efficient than seeking duplicate information. All the best. Tim. ----------------------------------------- Tim Moses Tel: 613.270.3183