In the case of local staging, after first enabling, there are few portletPreferences with ownerId = 0, ownerType = 3, plid = 0, see database portletPreferences table. For example, SiteTeamPortlet, DDLPortlet, PageCommentsPortlet, PageRatingPortlets, etc.
In the case of remote staging, publish to live. There will be a portletPrerences for changeSetPortlet with ownerId = 0, ownerType = 3, plid = 0, see database portletPreferences table for live site.
When you have a preferences of 0, 3, 0, there is no way to tell which site or page this preference belong to. All sites or pages will be sharing the same preferences, which is obviously not we wanted.