If all the sleepers were full, and they all stayed until 6:30, then there could be a situation [possibly] where the crew was paid until arrival (ie: 4:30 AM) and yet they have to keep working for maybe up to an hour after everyone leaves. I don't think any of them would care to work for 3 hours for free, if that is indeed how it works.
I don't have any specific knowledge that would contradict that theory, but if that's actually true, then--despite all the talk on here
about the all-powerful employee unions--this would appear to be a case where the employee is getting hosed. I know the
"pay until arrival" rule applies generally to LD trains, but this is clearly a different situation since passengers are explicitly
permitted to stay on board until a time certain.
That said, in my case if an SCA wanted to leave and let me stay on board by myself, I'm perfectly happy with that. But I can
understand why that wouldn't be a terribly good policy.