I take quite a few redeyes and since the basket-o-snacks are terrible, I always ask for something from the back. Only once did the F FA say that those are for economy passengers and you have what is provided here. I told her there was never a problem getting something but she wouldn't budge. Being a ex-CO crew, I went to the back of the plane where the ISM was and asked her. She was horrified that the FA said what she said and offered to give me anything I wanted. But it only happened once. And sometimes after lunch/dinner in F I'll ask for some Pringles. Never had an issue even when getting fed.