I had a flight a few weeks ago where Southwest sent me a message a few hours prior to departure that it was going to be 50 minutes delayed, and on the airport monitors it showed the same delay. I slowly made my way to the gate, got there 20 min prior to the originally scheduled departure time, the monitors still showed the delay, but they were already boarding the B boarding group. The plane took off pretty much on time, and was no more than 2/3 full. As I had a boarding pass in the high Cs, I am pretty sure a whole lot of people missed the plane and had to wait until the next day. Go figure... Lesson: Show up on time, just in case.