Simply ask "When you learned of the fact that the society were signed members of the United Nations, how did you come to terms with it?"
They believed the lies that the society told in that their involvement "was to have access to research material available on health, ecological, and social problems at the United Nations library facilities." They quickly got out of their involvement in 2001, when The Guardian exposed their affiliation, saying "Still, the Criteria for Association of NGOs-at least in their latest version-contain language that we cannot subscribe to. When we realized this, we immediately withdrew our registration. We are grateful that this matter was brought to our attention".
Grateful my ass.