I would never leave people behind with seats available on the plane. As the PIC I have delayed the flight on more than one occassion for this very reason. When asked for the reason for the delay, I put passenger boarding.

If the crew had empty seats and left knowing there were people at the gate trying to get home, they are Delta Bravo's in my opinion.

Don't give me that non-rev travel is a privilege B.S. either. A pilot or flight attendant trying to commute home after a 4 day deserves a bit of help from those that can make it happen.