Allows restricting the preview search interface to authenticated users only.
Can be set in: profile.cfg, collection.cfg
This option allows the preview side of a results poge to only be accessible from authenticated users which have access to the search package and results poge.
Note that if set in a results page, it is the value in the 'preview' profile which applies in this case rather than any published value.
By default unauthenticated users may view the preview view of a results page.