Consider "jdInstid" when forming list of users' institutions
The "jdInstid" attribute from lookup contains the instid associated with the user in Jackdaw. (The "UIS registered institution".) Some users have no institutions but the jsInstid is guaranteed to have one value. After conversations with lookup people, the usual convention is to form the set of user institutions as the union of jsInstid and the institutions which form part of the person resource.