I am a current CIA student that just got back from externing at one of NYC's big name restaurants. Yes the official policy of the school is no profanity in the kitchen, in practice, however, it is far from the truth. I have been in class a heard a bevy of explitives, some of which were espoused from the very "professional" chef instructors. I have even dropped the occasional F bomb here and there in class. It just comes with the territory. If someone from administration is in the class you could hear a pin drop, but if it is only us students and our chef, it is a looser environment. When I was on extern, some of the language in the kitchen would have made a sailor blush, and this is at a ultra high end restaurant. Never in front of guests though and never in front of people that you didn't know. I think it all stems from the sense of camraderie in the kitchen more than anything. If a person trusts you in the kitchen, they don't need to be all prim and propper, if they don't trust you, they are going to be on their best behavior. A kitchen is like a family, and I have no problem letting a few bad words slip in front of my family.