This feature is necessary to avoid sending out several mailings that might need to be unscheduled due to unforeseen, last minute situations - e.g. cancellations, close-outs, changes, discrepancies, etc...

If we urgently have to stop a group of emails at the last minute, it's impossible to unschedule them all one at a time, which is the current configuration in WCA. This results in emails going out that should have been stopped.