Thanks. It is a good start...
If I right-click a layer, unfortunately, options to View User or Disconnect are greyed out. Once you know there are existing locks, if you suspect a Feature Service locking a layer after publishing, apart from an Administrator, as I layer owner, can I stop the service to remove temporarely the lock? Otherwise, publishing layers can cause problems for database administration...
Another idea, is there a better workflow to refresh a layer on which a Feature Service is based? I mean replacing the data source by a brand new layer with same schema and name...