We've started using index data in some cases for static analysis. One of the things we've noticed doing this is that ACL information, which can sometimes be useful for our uses, isn't part of the index. Is ACL info something that would make sense to live in the index? In general how are the decisions of what should live in the index made?
speaking for myself, ACL seems useful for autocompleting only items valid in the current scope. Another thought is for search, ex you might want to limit results that are available publicly.