I find this odd, but it is done regularly at my school. Every single person calls the principal and secretary "Mrs. Name". There are other teachers at the school that have introduced themselves to me as Mrs. Name. I feel odd calling an adult Mrs. or Mr. when I work with them every day. I guess this was more common long ago, but it feels awkward to be so formal now. Is it done at your school or does everyone just use first names when the kids aren't around?