A good GA will make an announcement in the terminal, and if on their toes, they might in the RCC. I was in a similar situation on a LAX-IAD flight....we were given the new departure time (about a 6 hour delay)......about 20 of us went to the RCC, told the front desk agent what flight we were on.

Not sure if it was ever changed on the monitors or not......but none of us seemed to be keeping on top of things. Naps, phone calls, lunch, whatever. Suddenly one of the wives walked into the RCC and told us the flight was gone. Yeah, sure!

Well, she was right, and the embarrassed front desk agent admitted she had not looked out for this flight. About 10 of us flew out that afternoon and the other 10 were on the red-eye!

I learned a lesson.