I do not think that that is the whole story.
When I select only identifiers and attributes (no facts), then the SQL generated is automatically fetched as a distinct set. From a rollup reporting perspective this would be the sensible thing to do, cause I would be interested in the unique combinations that make up the set and not the complete recordset from the database.
Actually this was not covered in the fasttrack course in any way, so perhaps one of the forum guru's could shed some light on how the defaults are set.
Ties Blom