It is entirely dependent on the location and staffing at the time. The primary issue is locating the bag and physically moving it to the new preload for the new flight. There may or may not be time and that takes into account staffing at that point.

Bottom line is you cannot depend on this and the variables such as how many minutes to departure for the standby flight may make all the difference. Remember that if WN does agree to this and then fails, it is obligated to deliver your bag when it does arrive, a very expensive process.