Publishing Site and SEO

With the new website builder we have the option to publish and then at another point in time we can change the current domain to point to that site. So ... if published, but not really ready to go 'live' so-to-speak aren't we giving the search engines duplicate content, something we all know can be really bad for SEO.
The solution seems to be to use the Hide from Search Engines option. And then when we're ready to go live we would need to go through and remove that option. Yipes! if someone has a bazillion pages.
Or maybe I'm misunderstanding about the publishing aspect.