I have heard of this being a policy issue. I have heard of this being an issue of professional relationship vs. friendship. If the friendship is based on meeting and getting to know someone on a professional level, then it is perhaps unethical to be outside "friends". However, if you meet someone who happens to be a nurse, then that nurse in turn becomes your health care provider, that is different. Which stinks, as there are lots of patients that I just think are awesome and funny and wonderful and could see becoming fast friends, but it is inappropriate. And it stinks.