I will cut them some slack as its the arrival time that really matters not the departure time and time can be made up in the air, in taxitime, faster boarding, better routing etc, so its still possible to arrive ontime even if departing after scheduled time. Additionally, once you post a delay, people don't show up until the new departure time, and if things are ready to go a few minutes ahead, its best to get people boarded so you can leave quickly. At the same time (and I know this is what you are getting at) DL takes forever to post delays even once it becomes mathematically impossible to have an on-time arrival. For those of us with short connections it would be nice if they could post the delays sooner, so we are eligible to change flights and not risk misconnects
