If a user that connects to share on a Non-SSO enabled browser the "Alfresco is running without Share Services..." message appears even if the alfresco-share-services is installed.
I applied the workaround in
MNT-15500 and the message disappeared.
In share-header.lib.js the alfresco-api is used to get this information
It is often the case that an admin has to connect with non-SSO to login in as admin (different user that they are currently logged in with in windows) and get this message in error.
Also for many other reasons there are options to connect when not in SSO environment, such as users connecting via vpn.
For what I can tell it is only in this case the remote connect to alfresco-api is used, but if used elsewhere would break functionality for non-SSO users.