I had a rare experience where I was at the hospital and the admissions person asked me religious preference. I shared I was a Pastafarian. I got the usual strange look so I went onto explain. Her response, "so your really just mocking religion". I really felt bad because this was obviously upsetting to her. I have no interest in making fun in someones religious beliefs. I would rather have an honest discussion and help people better see reality. Lesson learned, now when asked I just say none or agnostic.
I live in a rural area, and find it annoying that so many nurses and hospital workers decorate their workspaces with Bible quotes and religious art. When asked at a hospital for religious affiliation, it's often just easier to say "Unitarian" -- and if you happen to actually have need and a Unitarian shows up, they will understand agnosticsm/atheism.