You are correct, Sytrace. I had visions of hearing something in code and my family wondering if we were supposed to be doing something at that time.
Many years ago, my husband and I had a bit of an adventure. We were in Russia and going by train from Moscow to Kazan (about 15 hours). We had a sleeping car, which we were sharing with one other person. This train looked like it had seen duty bringing troops to the front during WWII, but it ran and did the job. Anyway, about 1 in the morning, the train stopped. We looked out and there wasn't a station anywhere. We wondered why it would be stopping. We don't speak Russian and our cabin mate (and translator) was obliviously asleep. Then we heard men talking in the hall and going to all the doors and trying them. DH and I were scared, because, well, we didn't know what was going on. Eventually the train got back on it's way and it was a non-event for us, but the wondering and the fear made it really hard to get back to sleep.
So, I know if there are random codes over an intercom system at 1am, at very least, we will all be wondering if we're supposed to be evacuating the ship. But, if they make it clear what the correct actionable message is, I know my family will sleep better, although there will be prayers said, if the message is Bright Star.