In short, I think many customers prefer over communicating instead of no or little communication. Airline operations are incredibly dynamic and I'm perfectly fine if Soutwest wants to let me know everytime a flight I'm scheduled to take has an estimated time change. Of course, the departure time can always be pulled forward and you should be at the airport in plenty of time to depart at the originally scheduled departure time. Perhaps Southwest should add a more proment disclaimer to these alerts so that customers know to not rely on projected delayed departure times. It was very generous of Southwest to provide a voucher as a goodwill gesture for this inconvenience. You should absolutely share your feedback with them.