I've always thought of it as something that happens to men, but maybe I've fallen for the sitcom stereotype?
I have a friend. Someone I really know as part of a group. We go out together a lot as a group, usually drinking, dancing, to see a band. He often sits with me, he's quite tactile with me, we dance a lot. Whenever someone "notices" , which they do a lot, he'll say something like "were just friends, I'd hate to spoil our friendship".
He's probably right, it would be stupid, but does he mean it or is he persuading himself or just not interested in anything else?