Switching the veteran seems unfair

Its a given that with the same set of chefs, 2 different veterans will not score the same. And with this format, with 4 chefs, it matters much more than before.

It seems to be happening rather more. Obviously they can't avoid emergencies, but it seems these are not and its obvious who are the busy chefs who can't be there the whole week. Why can't they plan in advance, and if not get someone else?