I occasionally help at my dear friend's cafe. There is one lady she is a regular customer, she is gluten free. She caused us that she has almost died because of us because we served her gluten free food with "dirty" tongs. She was at the hospital. This is really hard to say if that was because of us. None could exactly say what caused her such a bad reaction for gluten. We all feel gutted even we know we have done nothing wrong and used tongs only for gluten-free food, but yet we do serve gluten as well. She is still coming back and give us very hard time every time. Treating all staff as bad as you can imagine. She is not polite. My friend is tried to please all customers, of course. But this lady just seeking for attention in my humble opinion. If I would have almost died, I would not come back. Her behavior is bizarre. Of course, we never want to harm anybody and welcome all customers, but also everyone want to be treated with respect. As an owner of cafe how would you deal with such a customer?