There's no substitute for leadership establishing a culture of meeting discipline. By and large, every org will follow the example leadership sets.
If leadership blesses this cutesy little five-minutes-late maneuver, implicitly accepting that meetings don't end on time, then meetings won't end on time at 5 after the hour either.
Any meeting without an agenda is a waste of time.
Some meetings are more important than others. So losing 5 minutes of a useless meeting is better than not going over 5 minutes for the important meeting.
Everyone wants to think their time is valuable, but this is relative.