I hate the whole naming who isn't Nancy part of the show and I do think it's just the BBC trying to stir up trouble and what they think makes better tv. Personally I'd much rather believe that they all got along, obviously when you're thrust together witha group of strangers like they have been, you are going to get along with some people better than others and we have definitely seen that, but that doesn't mean they dislike everyone else, they just aren't as close.
Although I have wondered about the relationship between Sam and Rachel, I would still like to think that they do get along ok, but just have to pick someone, the fact that they always pick each other probably makes it easier when they are asked again. That way neither needs to feel bad or upset about it.
Personally though I would just refuse to answer the question, I'm very aware now that these programmes are all edited to make things look different to how they are and personally I wouldn't say anything that could be made to look bitchy or mean when it perhaps wasn't intended like that. I think they should all just refuse to answer it. I would have been interested to see how Sarah handled it, maybe she would have played along like everyone else but it didn't seem in her nature to name someone like that.