Tag that renders the tag body if the current user is not known to the system, either because they
haven't logged in yet, or because they have no 'RememberMe' identity.
Tag that renders the tag body only if the current user's identity (aka principals) is remembered from a
successful authentication during a previous session and the user has not executed a successful authentication
attempt during their current session.
Tag that renders the tag body if the current user known to the system, either from a successful login attempt
(not necessarily during the current session) or from 'RememberMe' services.