Alan and I had a similar experience at Memphis while boarding the CONO. No one ever told us anything about waiting for the Conductor, so when the train arrived we found our car and got on it. After the train started moving the Conductor came to yell at us, and we basically told him we are not mind readers. If he wanted someone to wait he should have informed them with a sign or something on the platform or the waiting room instead of yelling. The saving grace was he did not threaten to eject us.
, which would have been inconvenient, since all the Sleeper boardings were actually told by the station guy to just go and board, and there were more than half a dozen of us. He would have had to empty out more than a third of his entire load.