Actually, it is not uncommon to have some softs before the Passholders Preview. The announced passholders previews pretty much guarantee that it will have a long line for them. So they usually run at least a few regular unannounced softs to get the crew up to speed before they hold the preview. A Passholder Preview is NOT like a soft open where they can close at any moment because of issues with the ride without MAJOR complaints from the passholders. People will expect it to be running during these previews. The order in which they usually open an attraction is , Cast Previews, softs, annual passholders preview, more softs, grand opening.