Should head chefs abandon their ship?
It is very uncommon for chefs to leave their kitchen posts when their restaurant is open. Most of them take their days off when the restaurant is closed. For instance, during Christmas it is hard to find a fine restaurant which is not closed for the holiday season or during August for the same reason.
There are of course some important reasons, which may keep chefs away from their kitchens. One being awards. If they are being honored related to their profession, they usually attend the event. Another reason would be related restaurants which require their attendance.
So, unless there is a special event or some other personal, or professional business, one would assume that fine chefs would be holding their positions.
It makes sense. Chefs are like captains, or pilots. Other people can do individual tasks but the person in charge should be physically in the kitchen during service hours.
Unless of course, somebody else is in charge, besides the big famous name on the door. This is how it usually works at restaurants which are owned by world famous chefs and are just one of many restaurants that chef owns or operates.