Ryan ---
Since I've retired, I've cleverly misplaced my most recent Service Standards Manual (which was just updated this past spring). So I can't give you a current rule citation. However, I found one from 2002, and I'm sure the rule today is the same or very similar. Chapter 13 is entitled "On-Board Services Crew Functions". Under "Train Attendant - Sleeping Car; Responsibilities Upon Departure and Enroute", item number 8 says "Do not permit unauthorized passengers in the sleeping car. If strangers enter the car, especially late at night, ask them if they need any assistance. If their reasons are not valid, politely direct them to the appropriate car." This can be found on page 13-25 of the 2002 Service Standards Manual.
We have always considered a valid sleeping car ticket to be a valid reason for being there, and any other ticket an invalid reason for being there. We have always tried to approach such "strangers" (as the rule calls them) in a friendly manner so as to minimize the possibility of any unpleasantness. But the rule's first three words tell the story: "DO NOT PERMIT......"
Maybe I've told this story before: Several years ago I was working one of the Auto Train's sleepers when a young man came from the coaches into the sleeper. When I stopped him, he told me he was just looking around. He wanted to continue through the train and check out the other sleepers as well. I told him my car was fully reserved, so there were no rooms I could show him. ""But I just want to look around," he insisted. I told him privacy was one of the things the sleeper passengers were paying extra for. I told him he could have one of the ticket agents show him around when we arrived at our destination the next morning. There would be time for that while he waited for his automobile to be off-loaded, and they could also give him all the info he might need for future travel, including sleeper ticket rates, etc. "But I just want to look around", he continued. That's when I knew we weren't getting anywhere so I said "As I said, Sir, these passengers are paying extra for privacy, and I'm here to make sure you DON'T look around".
Remember the story about the mule that was well-trained & a willing worker? Yes, he would work, but you had to break a 2 x 4 over his head to get his attention first.
Tom