I had a similar situation a couple of weeks ago. I was driving a bus for one school (where I did my student teaching) and heard the principal of another middle school asking one of his bus drivers if a certain person was coming in that day because he needed subs and was "short" by about 3 or 4. On my way home after the bus route, I called the secretary of that school, whom I know personally, and said I was just "touching base" with schools I haven't heard from in a while for sub assignments. She said "Well, if anything comes up, I'll definitely give you a call". I sooo wanted to say "Then you've already found the 4 subs you were needing about 45 minutes ago?" I'm not sure what's going on with the secretary. We did work together on a different job several years ago and she is friendly towards me, but she is also the kind of person I feel will say one thing to my face and do something entirely different behind my back. So, I'm thinking I will just bypass her and speak directly with the principal. I subbed at their school several times last year and - to the best of my knowledge - they had no issues with my work or classroom management.