Originally Posted by
beerup
...and just to add, it's not always transparent whether a flight is rescheduled or delayed from the original scheduled time. Therefore, the PAX may not know which of the scenarios apply. Often1's suggestion of going to the gate and asking the GA, if present, whether you can leave or not is sound advice.
IME asking the GA whether you can go to the lounge to wait always results in a NO answer, even when there is absolutely no way that the flight can leave in the next hour.