A family from Girdwood, Alaska was on the Costa Concordia and has told their story in a local publication. (Girdwood is a small town about 35 miles south of Anchorage, and is the site of the Alyeska Ski Resort.) After boarding, they had gone to their cabin and slept through the initial collision with the rocks. Later, awakened by a ship's alarm, they were told it was just "a power outage". However, when the ship started listing, they made a very sensible choice:

“I just said, ‘let’s just go up on deck and be safe, and we’ll watch the stars. It’s probably nothing, but I don’t feel comfortable staying in the room down in this maze of hallways.’ And we really weren’t familiar with the boat yet, having been on there for only a few hours. We basically got on dead tired, had dinner and went to bed. And we did not know the way out.”

I think the take away message is, if things don't feel right, they probably aren't right. Then it's definatly time to at least start thinking about "what if". Note that they also had the good sense to grab a headlamp from their stuff, and have the kids get fully dressed.