As a chef, I'm going to throw in my 2 cents on this...
If consuming butter, cream or fat is something that your body can't handle, then don't eat meals that have butter, cream or fat in them. If you were allergic to flour, would you be ok with eating a meal that had "just a little bit" of flour in it? No, you wouldn't. You wouldn't be stupid enough to risk it. So, if you can't eat certain foods, why would you be ordering a dish that has those foods in it to begin with?
That's your responsibility as a customer. If someone orders Chicken Alfredo at my restaurant, eats it and gets sick because they can't eat dairy (alfredo sauce has cream and cheese in it), it's not my fault. It's their fault because they were stupid enough to order something that they couldn't eat.
I'm allergic to penicillin and I'll get sick if I eat it. If I am at a restaurant and I see "Gorgonzola Rigatoni" on the menu, but the waitress assures me that there's not that much gorgonzola in the dish, I'm still not going to order it. There is penicillin in bleu cheese. Gorgonzola is a type of bleu cheese. Even if it's just a little bit, it would still make me sick. So, I'm not going to order it.
If I do order it, but the cook in the kitchen decides to add a lot of gorgonzola for some reason and I get sick, it's still my fault for eating food that I'm not supposed to be eating.
Also, she was talking about adding extra butter, cream or sauce to a dish. There is 100% nothing harmful or life threatening about that.
Sorry maybe I have totally misread or understood her post. I'm not allergic or anything like that but because my family and I grow most of our own foods and eat limited processed foods we are careful not to over do it when we go out. When you have been eating like this for years sometimes it can make a difference to how your body handles things. We are still able to eat oils and butter but not in large quantities, or not if someone were to deliberately tamper with even more into our meals.
I just expect that when I order something it comes prepared the way the chef describes it to me. I often ask or speak to a chef if we dine out, which is not often. I hope that has explained my situation a bit better.
I understood her post that she was deliberately adding extra oils and fats to someones food. That's all.
alas, they all closed in Minnesota so now we have nowhere to go for our late night doughnut fix...sad world 
i'd be a lot heavier!